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  • richardmitnick 10:50 pm on September 2, 2022 Permalink | Reply
    Tags: "New Fur for the Quantum Cat. Quantum materials:: entanglement of many atoms discovered for the first time", , , , , , , , , Superconductivity, , The scientists discovered an entirely new type of quantum phase transitions where entanglement takes place on the scale of many thousands of atoms instead of just in the microcosm of only a few.,   

    From The Dresden University of Technology [Technische Universität Dresden] (DE) And The Technical University of Munich [Technische Universität München] (DE): “New Fur for the Quantum Cat. Quantum materials:: entanglement of many atoms discovered for the first time” 

    From The Dresden University of Technology [Technische Universität Dresden] (DE)

    And

    Techniche Universitat Munchen

    The Technical University of Munich [Technische Universität München] (DE)

    9.2.22
    Prof. Matthias Vojta
    Technische Universität Dresden
    Chair of Theoretical Solid State Physics
    Cluster of Excellence ct.qmat – Complexity and Topology in Quantum Matter
    Co-spokesperson
    Tel.: +49 351 463-34135
    Matthias.Vojta@tu-dresden.de

    1
    Schroedinger’s cat with quantum fur: In the material LiHoF4, physicists from the universities of Dresden and Munich have discovered a new quantum phase transition at which the domains behave in a quantum mechanical fashion. Credit: C. Hohmann, MCQST.

    Be it magnets or superconductors: materials are known for their various properties. However, these properties may change spontaneously under extreme conditions. Researchers at the Technische Universität Dresden (TUD) and the Technische Universität München (TUM) have discovered an entirely new type of such phase transitions. They display the phenomenon of quantum entanglement involving many atoms, which previously has only been observed in the realm of few atoms. The results were recently published in the scientific journal Nature [below].

    New Fur for the Quantum Cat

    In physics, Schroedinger’s cat is an allegory for two of the most awe-inspiring effects of quantum mechanics: entanglement and superposition. Researchers from Dresden and Munich have now observed these behaviors on a much larger scale than that of the smallest of particles. Until now, materials that display properties like, e.g., magnetism have been known to have so-called domains – islands in which the materials properties are homogeneously either of one or a different kind (imagine them being either black or white, for example). Looking at lithium holmium fluoride (LiHoF4), the physicists have now discovered a completely new phase transition, at which the domains surprisingly exhibit quantum mechanical features, resulting in their properties becoming entangled (being black and white at the same time). “Our quantum cat now has a new fur because we’ve discovered a new quantum phase transition in LiHoF4 which has not previously been known to exist,” comments Matthias Vojta, Chair of Theoretical Solid State Physics at TUD.

    Phase transitions and entanglement

    We can easily observe the spontaneously changing properties of a substance if we look at water: at 100 degrees Celsius it evaporates into a gas, at zero degrees Celsius it freezes into ice. In both cases, these new states of matter form as a consequence of a phase transition where the water molecules rearrange themselves, thus changing the characteristics of the matter. Properties like magnetism or superconductivity emerge as a result of electrons undergoing phase transitions in crystals. For phase transitions at temperatures approaching the absolute zero at -273.15 degrees Celsius, quantum mechanical effects such as entanglement come into play, and one speaks of quantum phase transitions. “Even though there are more than 30 years of extensive research dedicated to phase transitions in quantum materials, we had previously assumed that the phenomenon of entanglement played a role only on a microscopic scale, where it involves only a few atoms at a time,” explains Christian Pfleiderer, Professor of Topology of Correlated Systems at the TUM.

    Quantum entanglement is one of the most astonishing phenomena of physics, where the entangled quantum particles exist in a shared superposition state that allows for usually mutually exclusive properties (e.g., black and white) to occur simultaneously. As a rule, the laws of quantum mechanics only apply to microscopic particles. The research teams from Munich and Dresden have now succeeded in observing effects of quantum entanglement on a much larger scale, that of thousands of atoms. For this, they have chosen to work with the well-known compound LiHoF4.

    Spherical samples enable precision measurements

    At very low temperatures, LiHoF4 acts as a ferromagnet where all magnetic moments spontaneously point in the same direction. If you then apply a magnetic field exactly vertically to the preferred magnetic direction, the magnetic moments will change direction, which is known as fluctuations. The higher the magnetic field strength, the stronger these fluctuations become, until, eventually, the ferromagnetism disappears completely at a quantum phase transition. This leads to the entanglement of neighboring magnetic moments. “If you hold up a LiHoF4 sample to a very strong magnet, it suddenly ceases to be spontaneously magnetic. This has been known for 25 years,” summarizes Vojta.

    What is new is what happens when you change the direction of the magnetic field. “We discovered that the quantum phase transition continues to occur, whereas it had previously been believed that even the smallest tilt of the magnetic field would immediately suppress it,” explains Pfleiderer. Under these conditions, however, it is not individual magnetic moments but rather extensive magnetic areas, so-called ferromagnetic domains, that undergo these quantum phase transitions. The domains constitute entire islands of magnetic moments pointing in the same direction. “We have used spherical samples for our precision measurements. That is what enabled us to precisely study the behavior upon small changes in the direction of the magnetic field,” adds Andreas Wendl, who conducted the experiments as part of his doctoral dissertation.

    From fundamental physics to applications

    “We have discovered an entirely new type of quantum phase transitions where entanglement takes place on the scale of many thousands of atoms instead of just in the microcosm of only a few,” explains Vojta. “If you imagine the magnetic domains as a black-and-white pattern, the new phase transition leads to either the white or the black areas becoming infinitesimally small, i.e., creating a quantum pattern, bevor dissolving completely.” A newly developed theoretical model successfully explains the data obtained from the experiments. “For our analysis, we generalized existing microscopic models and also took into account the feedback of the large ferromagnetic domains to the microscopic properties,” elaborates Heike Eisenlohr, who performed the calculations as part of her PhD thesis.

    The discovery of the new quantum phase transitions is important as a foundation and general frame of reference for the research of quantum phenomena in materials, as well as for new applications. “Quantum entanglement is applied and used in technologies like quantum sensors and quantum computers, amongst other things,” says Vojta. Pfleiderer adds: “Our work is in the area of fundamental research, which, however, can have a direct impact on the development of practical applications, if you use the materials properties in a controlled way.”

    Science paper:
    Nature

    See the full article here.

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     Technische Universität München Campus

    The Technical University of Munich [Technische Universität München] (DE) is a public research university in Munich, with additional campuses in Garching, Freising, Heilbronn, Straubing, and Singapore. A technical university that specializes in engineering, technology, medicine, and the applied and natural sciences, it is organized into 11 schools and departments, and supported by numerous research centers.

    A University of Excellence under the German Universities Excellence Initiative, TUM is consistently ranked among the leading universities in the European Union and its researchers and alumni include 16 Nobel laureates and 23 Leibniz Prize winners.

    Departments

    Aerospace engineering, geodesy
    Ottobrunn

    Department of Architecture
    Munich

    Department of Civil, Geo and Environmental Engineering
    Civil engineering, environmental engineering, earth science
    Munich

    Department of Chemistry
    Garching

    Department of Electrical and Computer Engineering
    Munich

    Department of Informatics [Computer science]
    Garching

    Department of Mechanical Engineering
    Garching

    Department of Mathematics
    Garching

    School of Medicine
    Munich

    Department of Physics
    Garching

    Department of Sport and Health Sciences
    Munich

    School of Education
    Munich

    School of Governance
    Munich

    School of Management
    Munich

    School of Life Sciences
    Freising

    Research

    The Technical University of Munich is one of the most research-focused universities in Europe. This claim is supported by relevant rankings, such as the funding ranking of the German Research Foundation and the research ranking of the Centre for Higher Education.

    Under the German Universities Excellence Initiative, TUM has obtained funding for multiple research clusters, including e-conversion (energy technology), MCQST – Munich Center for Quantum Science and Technology(DE) (quantum mechanics), ORIGINS (astrophysics, biophysics and particle physics), and SYNERGY (neurology).

    In addition to the schools and departments, TUM has set up numerous research centers with external cooperation partners.

    Integrative research centers (IRCs) combine research with teaching. They include the TUM Institute for Advanced Study (TUM-IAS), the TUM-Munich Center for Technology in Society (MCTS), TUM-Munich Data Science Institute (MDSI), TUM-Munich School of Engineering , TUM-Munich Institute of Biomedical Engineering, and the TUM-Munich Institute of Robotics and Machine Intelligence.

    Corporate research centers (CRCs) carry out research independently of the schools and departments, cooperating with industry partners for application-driven research. They include the research reactor FRM II, the Center for Functional Protein Assemblies (CPA), the Catalysis Research Center (CRC), the center for translational Cancer Research (TranslaTUM), the Walter Schottky Institute (WSI), the Hans Eisenmann-Zentrum for Agricultural Science, and the Institute for Food & Health (ZIEL).

    Rankings

    TUM is ranked first in Germany in the fields of engineering and computer science, and within the top three in the natural sciences.

    In the QS World Rankings, TUM is ranked 19th (worldwide) in engineering and technology, 28th in the natural sciences, 29th in computer science, and 50th place overall. It is the highest ranked German university in those subject areas.

    In the Times Higher Education World University Rankings, TUM stands at 38th place worldwide and 2nd place nationwide. Worldwide, it ranks 14th in computer science, 22nd in engineering and technology, and 23rd in the physical sciences. It is the highest ranked German university in those subject areas.

    In the Academic Ranking of World Universities, TUM is ranked at 52nd place in the world and 2nd place in Germany. In the subject areas of computer science and engineering, electrical engineering, aerospace engineering, food science, biotechnology, and chemistry, TUM is ranked first in Germany.

    In the 2021 Global University Employability Ranking of the Times Higher Education World Rankings, TUM was ranked 13th in the world and 4th in Europe. TUM is ranked 7th overall in Reuters’ 2019 European Most Innovative University ranking.

    The TUM School of Management is triple accredited by the European Quality Improvement System (EQUIS), the Association to Advance Collegiate Schools of Business (AACSB) and the Association of MBAs (AMBA).

    Partnerships

    TUM has over 160 international partnerships, ranging from joint research activities to international study programs. Partners include:

    Europe: ETH Zurich, EPFL, ENSEA, École Centrale Paris, TU Eindhoven, Technical University of Denmark, and Technical University of Vienna
    United States:The Massachusetts Institute of Technology , Stanford University, Northwestern University, University of Illinois, Cornell University, University of Texas-Austin, and Georgia Tech
    Asia: The National University of Singapore, Multimedia University, Hong Kong University of Science and Technology, Huazhong University of Science and Technology, Tsinghua University, University of Tokyo, Indian Institute of Technology Delhi, Amrita University, and Sirindhorn International Institute of Technology.
    Australia: Australian National University, University of Melbourne, The Royal Melbourne Institute of Technology (AU).

    Through the Erasmus+ program and its international student exchange program TUMexchange, TUM students are provided by opportunities to study abroad.e, TUM students are provided by opportunities to study abroad.

    The Dresden University of Technology [Technische Universität Dresden] (DE) is a public research university, the largest institute of higher education in the city of Dresden, the largest university in Saxony and one of the 10 largest universities in Germany with 32,389 students as of 2018.

    The name Technische Universität Dresden has only been used since 1961; the history of the university, however, goes back nearly 200 years to 1828. This makes it one of the oldest colleges of technology in Germany, and one of the country’s oldest universities, which in German today refers to institutes of higher education that cover the entire curriculum. The university is a member of TU9, a consortium of the nine leading German Institutes of Technology. The university is one of eleven German universities which succeeded in the Excellence Initiative in 2012, thus getting the title of a “University of Excellence”. The TU Dresden succeeded in all three rounds of the German Universities Excellence Initiative (Future Concept, Graduate Schools, Clusters of Excellence).

    History

    In 1828, with emerging industrialization, the “Saxon Technical School” was founded to educate skilled workers in technological subjects such as mechanics; mechanical engineering and ship construction. In 1871 the year the German Empire was founded, the institute was renamed the Royal Saxon Polytechnic Institute (Königlich-Sächsisches Polytechnikum). At that time, subjects not connected with technology such as history and languages were introduced. By the end of the 19th century the institute had developed into a university covering all disciplines. In 1961 it was given its present name, Dresden University of Technology [Technische Universität Dresden].

    Upon German reunification in 1990 the university had already integrated the College of Forestry (Forstliche Hochschule) formerly the Royal Saxony Academy of Forestry, in the nearby small town of Tharandt. This was followed by the integration of the Dresden College of Engineering (Ingenieurshochschule Dresden); the Friedrich List College of Transport (Hochschule für Verkehrswesen) the faculty of transport science; and the “Carl-Gustav Carus” Medical Academy (Medizinische Akademi), the medical faculty. Some faculties were newly founded: the faculties of Information Technology (1991); Law (1991); Education (1993); and Economics (1993).

    In 2009 TU Dresden, all Dresden institutes of the Fraunhofer Society; the Gottfried Wilhelm Leibniz Scientific Community and the Max Planck Society and Forschungszentrum Dresden-Rossendorf soon incorporated into the Helmholtz Association of German Research Centres (DE), published a joint letter of intent with the name DRESDEN-Konzept – Dresden Research and Education Synergies for the Development of Excellence and Novelty, which points out worldwide elite aspirations, which was recognized as the first time that all four big post-gradual elite institutions declared campus co-operation with a university.

    Sciences

    With 4,390 students the Faculty of Mathematics and the Natural Sciences is the second-largest faculty at the university. It is composed of 5 departments: Biology; Chemistry; Mathematics; Physics; and Psychology. The departments are all located on the main campus. In 2006, a new research building for the biology department opened. In October 2006 the Deutsche Forschungsgemeinschaft decided to fund a new graduate school, the Dresden International Graduate School for Biomedicine and Bioengineering and a so-called cluster of excellence From Cells to Tissues to Therapies.

    Engineering

    The Faculty of Architecture comprises 6 departments. Currently, there are 1,410 students enrolled.
    The Faculty of Civil Engineering is structured into 11 departments. It is the oldest and smallest of the faculties. There are currently 800 students enrolled.
    The Faculty of Computer Science comprises six departments: Applied Computer Science; Artificial Intelligence; Software- and Multimedia-Technology; Systems Architecture; Computer Engineering; and Theoretical Computer Science. The faculty has 2,703 students.
    The Faculty of Electrical Engineering and Information Technology is organized into 13 departments. There are 2,288 students enrolled. The faculty is the heart of the so-called Silicon Saxony in Dresden.
    The Faculty of Environmental Sciences has 2,914 students. The faculty is located on the main campus, except for the Forestry department which is located in Tharandt. The Forestry department is the oldest of its kind in Germany. Its history goes back to the foundation of the Royal Saxon Academy of Forestry (Königlich-Sächsische Forstakademie) in 1816.
    The Faculty of Mechanical Engineering comprises 19 departments and has 5,731 students. It is the largest faculty at TUD.
    The Faculty of Transport and Traffic Sciences “Friedrich List” is the only of its kind in Germany covering transport and traffic from economy and system theory science to electrical, civil and mechanical engineering. There are 1,536 students enrolled.

    Humanities and Social Sciences

    The Faculty of Business and Economics comprises five departments: Business Education Studies (Wirtschaftspädagogik); Business Management; Economics; Business Information Systems; and Statistics. There are 2,842 students enrolled.
    The Faculty of Education, located East of the main campus, has 2,075 students.
    The Faculty of Languages, Literature and Culture is structured into five departments: American Studies; English Studies; German Studies; Philology; Romance Languages; and Slavic Studies. There are 3,215 students at this faculty.
    The Faculty of Law is going to close in the next few years. Currently there are still 933 students enrolled. The TU Dresden has partially compensated the closure by establishing a private law school
    The Faculty of Philosophy comprises seven departments: Art History; Communications; History; Musicology; Political Sciences; Sociology; and Theology. There are 3,485 students enrolled.
    The School of International Studies is a so-called central institution of the university coordinating the law, economics and political sciences departments for courses of interdisciplinary international relations.

    Medicine
    The Carl Gustav Carus Faculty of Medicine has its own campus East of the city center near the Elbe river. Currently, there are 2,195 students enrolled. The faculty has a partnership with Partners Harvard Medical International.

    Research Centers
    Center for Advancing Electronics Dresden (cfaed) – Cluster of Excellence
    Center for Regenerative Therapies Dresden (CRTD) – Cluster of Excellence
    Dendro-Institute Tharandt at the TU Dresden
    The European Institute for Postgraduate Education at TU Dresden (EIPOS Europäisches Institut für postgraduale Bildung an der Technischen Universität Dresden e. V.)
    The European Institute of Transport (EVI Europäisches Verkehrsinstitut an der Technischen Universität Dresden e. V.)
    The Hannah Arendt Center for Research on Totalitarianism (HAIT Hannah-Arendt-Institut für Totalitarismusforschung an der Technischen Universität Dresden e. V.)
    Center for Media Culture (MKZ Medienkulturzentrum Dresden e. V. an der TU Dresden)
    Center for Research on Mechanics of Structures and Materials (SWM Struktur- und Werkstoffmechanikforschung Dresden GmbH an der Technischen Universität Dresden)
    TUD Vietnam ERC, the TU Dresden Vietnam Education and Research Center. The center offers a Master’s course in Mechatronics in Hanoi (Vietnam) since 2004.
    Center for Continuing Education in Historic Preservation (WBD Weiterbildungszentrum für Denkmalpflege und Altbauinstandsetzung e. V.)
    School of International Studies (Zentrum für Internationale Studien, ZIS in German)

     
  • richardmitnick 2:09 pm on August 19, 2022 Permalink | Reply
    Tags: "Physics Duo Finds Magic in Two Dimensions", A dream was born-the number one goal of condensed matter physics today: finding or engineering a substance that can superconduct electricity in our hot roughly 300-kelvin world., , Graphene (as its discoverers dubbed it) was a whole new category of substance — a 2D material., Graphene transformed Condensed Matter Physics., Jie Shan and Kin Fai Mak at Columbia University saw signs that flakes of molybdenite might be even more magical than graphene., Molybdenite-even to the trained eye-looks almost identical to graphite: a lustrous silvery crystal., Much research in condensed matter physics is a trial-and-error hunt for crystals that can keep their electrons paired or shepherd electrons in other wondrous ways., , , Shan and Mak have published an eye-popping eight papers in “Nature”., Shan and Mak’s group [now at Cornell University] has captured electrons behaving in unprecedented ways in these flat crystals., Superconductivity, Today that same flakiness is fueling a physics revolution-Graphene., Today that same flakiness is fueling a physics revolution., With its tendency to flake into powdery fragments molybdenite became a popular lubricant in the 20th century.   

    From “Quanta Magazine” : “Physics Duo Finds Magic in Two Dimensions” 

    From “Quanta Magazine”

    8.16.22
    Charlie Wood

    1
    Of his partnership with Jie Shan (left), Kin Fai Mak said, “One plus one is more than two.” Credit: Sasha Maslov and Olena Shmahalo for Quanta Magazine

    Molybdenite-even to the trained eye-looks almost identical to graphite: a lustrous silvery crystal. It acts similarly too, sloughing off flakes in a way that would make for a good pencil filling. But to an electron, the two grids of atoms form different worlds. The distinction first entered the scientific record 244 years ago. Carl Scheele, a Swedish chemist renowned for his discovery of oxygen, plunged each mineral into assorted acids and watched the lurid clouds of gas that billowed forth. Scheele, who eventually paid for this approach with his life, dying of suspected heavy metal poisoning at 43, concluded that molybdenite was a new substance. Describing it in a letter to the Royal Swedish Academy of Science in 1778, he wrote, “I refer here not to the commonly known graphite that one can acquire from the apothecary. This transition metal seems to be unknown.”

    With its tendency to flake into powdery fragments molybdenite became a popular lubricant in the 20th century. It helped skis glide farther through the snow and smoothed the exit of bullets from rifle barrels in Vietnam.

    Today that same flakiness is fueling a physics revolution.

    The breakthroughs started with graphite and Scotch tape. Researchers discovered by chance in 2004 that they could use tape to peel off flakes of graphite just one atom thick. These crystalline sheets, each a flat array of carbon atoms, had astonishing properties that were radically different from those of the three-dimensional crystals they came from. Graphene (as its discoverers dubbed it) was a whole new category of substance — a 2D material. Its discovery transformed condensed matter physics, the branch of physics that seeks to understand the many forms and behaviors of matter. Nearly half of all physicists are condensed matter physicists; it’s the subfield that brought us computer chips, lasers, LED bulbs, MRI machines, solar panels, and all manner of modern technological marvels. After graphene’s discovery, thousands of condensed matter physicists started studying the new material, hoping it would undergird future technologies.

    1
    The mineral molybdenite is often crushed into powdery fragments and used as an industrial lubricant. But physicists have discovered that 2D sheets of the hexagonal crystal conjure novel electron behaviors. Credit: Harold Moritz.

    Graphene’s discoverers received the Nobel Prize in Physics in 2010. That same year, two young physicists at Columbia University, Jie Shan and Kin Fai Mak saw signs that flakes of molybdenite might be even more magical than graphene. The lesser-known mineral has properties that make it tough to study — too tough for many labs — but it captivated Shan and Mak. The tenacious duo devoted nearly a decade to wrangling 2D molybdenite (or molybdenum disulfide, as the lab-grown version of the crystal is called) and a family of closely related 2D crystals.

    Now their effort is paying off. Shan and Mak, who are now married and run a joint research group at Cornell University, have shown that 2D crystals of molybdenum disulfide and its relatives can give rise to an enormous variety of exotic quantum phenomena. “It’s a crazy playground,” said James Hone, a researcher at Columbia who supplies the Cornell lab with high-quality crystals. “You can do all of modern condensed matter physics in one material system.”

    Shan and Mak’s group has captured electrons behaving in unprecedented ways in these flat crystals. They’ve coaxed the particles to merge into a quantum fluid and freeze into an assortment of icelike structures. They’ve learned to assemble grids of gigantic artificial atoms that are now serving as test beds for fundamental theories of matter. Since opening their Cornell lab in 2018, the master electron tamers have published an eye-popping eight papers in Nature, the most prestigious journal in science, as well as a slew of further papers. Theorists say the couple is expanding the understanding of what throngs of electrons are capable.

    Their research “is deeply impressive in many aspects,” said Philip Kim, a prominent condensed matter physicist at Harvard University. “It is, I would say, sensational.”

    Rise of 2D Materials

    A material’s attributes generally reflect what its electrons are doing. In conductors such as metals, for instance, electrons sail between atoms with ease, carrying electricity. In insulators like wood and glass, electrons stay put. Semiconductors like silicon fall in between: Their electrons can be forced to move with an influx of energy, making them ideal for switching currents on and off — the job of a transistor. Over the last 50 years, besides those three basic electron behaviors, condensed matter physicists have seen the lightweight charged particles behaving in many more exotic ways.

    One of the more dramatic surprises came in 1986, when two IBM researchers, Georg Bednorz and Alex Müller, detected [Zeitschrift für Physik B Condensed Matter (below)] a current of electrons moving through a copper oxide (“cuprate”) crystal without any resistance whatsoever.

    2
    In 1986, Georg Bednorz (left) and Alex Müller stumbled on a new family of copper-based materials called cuprates that could superconduct in far warmer temperatures than normal metals. Courtesy of IBM Research.

    This superconductivity — the ability of electricity to flow with perfect efficiency — had been seen before, but only for well-understood reasons in materials cooled to within a few degrees of absolute zero. This time, Bednorz and Müller observed a mysterious form of the phenomenon that persisted at a record-breaking 35 kelvins (that is, 35 degrees above absolute zero). Scientists soon discovered other cuprates that superconduct above 100 kelvins. A dream was born that remains perhaps the number one goal of condensed matter physics today: finding or engineering a substance that can superconduct electricity in our hot, roughly 300-kelvin world, enabling lossless power lines, levitating vehicles and other hyper-efficient devices that would significantly reduce humanity’s energy needs.

    The key to superconductivity is to coax electrons, which normally repel one another, to pair up and form entities known as bosons. Bosons can then collectively meld into a frictionless quantum fluid. Attractive forces that create bosons, such as atomic vibrations, can normally overcome electrons’ repulsion only at cryogenic temperatures or high pressures. But the need for these extreme conditions has prevented superconductivity from finding its way into everyday devices. The discovery of cuprates raised hopes that the right atomic lattice could “glue” electrons together so firmly that they’d stay stuck even at room temperature.

    Going on 40 years after Bednorz and Müller’s finding, theorists still aren’t completely sure how the glue in cuprates works, much less how to tweak the materials to strengthen it. Thus, much research in condensed matter physics is a trial-and-error hunt for crystals that can keep their electrons paired or shepherd electrons in other wondrous ways. “Condensed matter is a branch of physics that allows for serendipities,” said Kim. Such was the 2004 discovery of 2D materials.


    Merrill Sherman/Quanta Magazine

    Andre Geim and Konstantin Novoselov, working with graphite at the University of Manchester in the United Kingdom, discovered [Nature Materials (below)] a shocking consequence of the material’s flakiness. A graphite crystal contains carbon atoms arranged into loosely bound sheets of hexagons. Theorists had long predicted that without the stabilizing influence of the stack, heat-induced vibrations would break up a one-layer sheet. But Geim and Novoselov found that they could peel off stable, atomically thin sheets with little more than Scotch tape and persistence. Graphene was the first truly flat material — a plane on which electrons can slide around but not up and down.

    Hone, the Columbia physicist, discovered that the world’s thinnest material is somehow also the strongest [Science (below)]. It was a remarkable upset for a material that theorists thought wouldn’t hang together at all.

    What most intrigued physicists about graphene was how the carbon flatland transformed electrons: Nothing could slow them down. Electrons often get tripped up by the lattice of atoms through which they move, acting heavier than their textbook mass (an insulator’s immobile electrons act as if they have infinite mass). Graphene’s flat lattice, however, let electrons whiz around at a million meters per second — only a few hundred times slower than the speed of light. At that constant, blistering speed, the electrons flew as if they had no mass at all, blessing graphene with extreme (though not super) conductivity.

    A whole field sprang up around the wonder material. Researchers also began to think more broadly. Could 2D flakes of other substances harbor superpowers of their own? Hone was among those who branched out. In 2009, he measured some mechanical properties of graphite’s doppelgänger, molybdenum disulfide, then passed the crystal off to two optical specialists in the Columbia lab of Tony Heinz. It was a casual move that would change the careers of everyone involved.

    The molybdenum disulfide sample landed in the hands of Jie Shan, a visiting professor early in her career, and Kin Fai Mak, a graduate student. The young duo was studying how graphene interacts with light, but they had already started daydreaming about other materials. Graphene’s speedy electrons make it a fantastic conductor, but what they wanted was a 2D semiconductor — a material whose flow of electrons they could turn on and off, and which could therefore serve as a transistor.

    Molybdenum disulfide was known to be a semiconductor. And Shan and Mak soon found out that, like graphite, it gained additional powers in 2D. When they pointed a laser on 3D crystals of “moly disulfide” (as they affectionally call it), the crystals stayed dark. But when Shan and Mak ripped off layers with Scotch tape, hit them with a laser, and examined them under a microscope, they saw the 2D sheets shining brightly.

    Research from other groups would later confirm that well-made sheets of a closely related material reflect every last photon that hits them. “That’s kind of mind-boggling,” Mak said recently, when I met him and Shan in their shared office at Cornell. “You just have a single sheet of atoms, and it can reflect 100% of the light like a perfect mirror.” They realized that this property might lead to spectacular optical devices.

    Independently, Feng Wang, a physicist at the University of California, Berkeley, made the same discovery. A 2D material that was highly reflective and a semiconductor to boot caught the community’s attention. Both groups published their findings in 2010 [Nano Letters (below)]; the papers have since received more than 16,000 citations between them. “Everybody with lasers started getting very interested in 2D materials,” Hone said.

    By identifying moly disulfide as a second 2D wonder material, the two groups had made landfall on a whole continent of 2D materials. Moly disulfide belongs to a family of substances known as transition metal dichalcogenides (TMDs), in which atoms from the metallic middle region of the periodic table such as molybdenum link up with pairs of chemical compounds known as chalcogenides, such as sulfur. Moly disulfide is the only naturally occurring TMD, but there are dozens more [Nature Reviews Materials (below)] that researchers can whip up in labs — tungsten disulfide, molybdenum ditelluride and so on. Most form weakly bound sheets, making them susceptible to the business side of a piece of tape.

    The initial wave of excitement soon ebbed, however, as researchers struggled to get TMDs to do more than shine. Wang’s group, for one, fell back on graphene after finding that they couldn’t easily attach metal electrodes to moly disulfide. “That has been the stumbling block for our group for quite a few years,” he said. “Even now we are not very good at making contact.” It seemed that the main advantage of TMDs over graphene was also their biggest weakness: To study a material’s electronic properties, researchers must often push electrons into it and measure the resistance of the resulting current. But because semiconductors are poor conductors, it’s hard to get electrons in or out.

    Mak and Shan initially felt ambivalent. “It was really unclear whether we should keep working on graphene or start working on this new material,” Mak said. “But since we found it has this nice property, we continued to do a few more experiments.”

    As they worked, the two researchers became increasingly enchanted by moly disulfide, and by each other. Initially, their contact was professional, limited largely to research-focused emails. “Fai was often asking, ‘Where is that piece of equipment? Where did you put that?’” Shan said. But eventually their relationship, incubated by long hours and catalyzed by experimental success, turned romantic. “We just saw each other too often, literally in the same lab working on the same project,” Mak said. “The project working very well also made us happy.”

    All Physics All the Time

    It would take a partnership between two devoted physicists with iron discipline to bring the troublesome TMDs to heel.

    Academics always came easily to Shan. Growing up in the 1970s in the coastal province of Zhejiang, she was a star student, excelling in math, science and language and earning a coveted spot at the University of Science and Technology of China in Hefei. There, she qualified for a selective cultural exchange program between China and the Soviet Union, and she jumped at the chance to study Russian and physics at Moscow State University. “When you’re a teen, you’re eager to explore the world,” she said. “I didn’t hesitate.”

    Right away, she saw more of the world than she had bargained for. Visa troubles delayed her arrival in Russia by a few months, and she lost her seat in the language program. The authorities found her another course, and shortly after landing in Moscow she boarded a train and traveled 5,000 kilometers east. Three days later she arrived in the city of Irkutsk in the middle of Siberia at the onset of winter. “The advice I got was, ‘Never, ever touch anything without gloves,’” lest she get stuck, she said.

    Shan kept her gloves on, learned Russian in a single semester, and came to appreciate the stark beauty of the wintry landscape. When the course ended and the snow melted, she returned to the capital to begin her physics degree, arriving in Moscow in the spring of 1990, in the midst of the breakup of the Soviet Union.

    Those were chaotic years. Shan saw tanks rolling through the streets near the university as Communists tried to regain control of the government. On another occasion, just after a final exam, fighting broke out. “We could hear gunfire, and we were told to turn off the lights in the dorm,” she said. Everything, from food to toilet paper, was rationed through a coupon system. Nevertheless, Shan felt inspired by the resilience of her professors, who continued with their research despite the turmoil. “The conditions were tough, but many of the scientists had this kind of an attitude. They truly love what they do, despite what’s going on,” she said.

    As the world order collapsed, Shan distinguished herself, publishing a theoretical optics paper that caught Heinz’s eye at Columbia. He encouraged her to apply, and she relocated to New York, where she occasionally helped other international students get their footing in a foreign country. She recruited Wang to work in Heinz’s lab, for instance, and shared experimental tips. “She taught me how to be patient,” he said, and “how to not get frustrated with the laser.”

    Most researchers take a postdoctoral position after earning their Ph.D., but Shan joined Case Western Reserve University directly as an associate professor in 2001. Several years later, on a sabbatical, she returned to Heinz’s lab at Columbia. For once, her timing was fortuitous. She started collaborating with a charming and bright-eyed graduate student in Heinz’s group, Kin Fai Mak.

    Mak had followed a different, less tumultuous path to New York City. Growing up in Hong Kong, he struggled in school, as little besides physics made sense to him. “It was the only thing I like and was actually good at, so I picked physics,” he said.

    His undergraduate research at Hong Kong University of Science and Technology stood out, and Heinz recruited him to join Columbia’s booming condensed matter physics program. There, he threw himself into research, spending almost all his waking hours in the lab except for the occasional game of intramural soccer. Andrea Young, a fellow grad student (now a professor at the University of California, Santa Barbara), shared an apartment with Mak on West 113th Street. “I was lucky if I could catch him at 2 o’clock in the morning to cook some pasta and talk about physics. It was all physics all the time,” Young said.

    But the good times didn’t last. Shortly after an excursion to the Amazon rainforest in Colombia with Young, Mak fell ill. His doctors weren’t sure what to make of his puzzling test results, and he got sicker. A lucky coincidence saved his life. Young described the situation to his father, a medical researcher, who immediately recognized the signs of aplastic anemia — an unusual blood condition that happened to be the subject of his own research. “It’s actually really rare to get this disease, first of all,” Mak said. “And even rarer to get a disease in which your roommate’s father is an expert.”

    Young’s father helped Mak enroll in experimental treatments. He spent much of his final year of graduate school in the hospital and came close to death several times. Throughout the ordeal, Mak’s ardor for physics drove him to keep working. “He was writing PRL letters from his hospital bed,” Young said, referring to the journal Physical Review Letters. “Despite all of this, he was one of the most productive students ever,” Heinz said. “It was something of a miracle.”

    Further treatments eventually helped Mak make a full recovery. Young, himself a well-known experimentalist, would later quip about his interventions, “Among friends I call it my greatest contribution to physics.”

    Into the 2D Wilderness

    Mak moved on to Cornell as a postdoctoral researcher in 2012, by which time Shan had already returned to Case Western. They pursued individual projects with graphene and other materials, but they also continued to unlock further secrets of the TMDs together.

    At Cornell, Mak learned the art of electron transport measurements — the other main way of divining the movement of electrons, besides optics. This expertise made him and Shan a double threat in a field where researchers typically specialize in one type or the other. “Whenever I meet Fai and Jie I complain, ‘It’s unfair you guys do transport,’” Kim said. “What am I supposed to do?”

    The more the duo learned about TMDs, the more intriguing they got. Researchers typically focus on one of two properties of electrons: their charge and spin (or intrinsic angular momentum). Controlling the flow of electric charge is the foundation of modern electronics. And flipping electrons’ spin could lead to “spintronics” devices that pack more information into smaller spaces. In 2014, Mak helped discover [Science (below)]that electrons in 2D moly disulfide can acquire a special, third property: These electrons must move with specific amounts of momentum, a controllable attribute known as “valley” that researchers speculate might spawn yet a third field of “valleytronics” technology.

    That same year, Mak and Shan identified another striking feature of TMDs. Electrons are not the only entities that move through a crystal; physicists also track “holes,” the vacancies created when electrons hop elsewhere. These holes can roam a material like real positively charged particles. The positive hole attracts a negative electron to form a fleeting partnership, known as an exciton, in the moment before the electron plugs the hole. Shan and Mak measured the attraction [Physical Review Letters (below)] between electrons and holes in 2D tungsten diselenide and found it hundreds of times stronger than in a typical 3D semiconductor. The finding hinted that excitons in TMDs could be especially robust, and that in general electrons were more likely to do all sorts of weird things.

    4

    The couple secured positions together at Pennsylvania State University and started a lab there. Finally convinced that TMDs were worth betting their careers on, they made the materials the focus of their new group. They also got married.

    Meanwhile, Hone’s team at Columbia saw graphene’s properties get even more extreme when they placed it on top of a high-quality insulator, boron nitride. It was an early example of one of the most novel aspects of 2D materials: their stackability.

    Put one 2D material on top of another, and the layers will sit a fraction of a nanometer apart — no distance at all from the perspective of their electrons. As a result, stacked sheets effectively merge into one substance. “It’s not just two materials together,” Wang said. “You really create a new material.”

    Whereas graphene consists exclusively of carbon atoms, the diverse family of TMD lattices brings dozens of additional elements into the stacking game. Each TMD has its own intrinsic abilities. Some are magnetic; others superconduct. Researchers looked forward to mixing and matching them to fashion materials with their combined powers.

    But when Hone’s group placed moly disulfide on an insulator, the properties of the stack showed lackluster gains compared to what they had seen in graphene. Eventually they realized that they hadn’t checked the quality of the TMD crystals. When they had some colleagues stick their moly disulfide under a microscope capable of resolving individual atoms, they were stunned. Some atoms sat in the wrong place, while others had gone missing entirely. As many as 1 in 100 lattice sites had some problem, impeding the lattice’s ability to direct electrons. Graphene, in comparison, was the image of perfection, with roughly one defect per million atoms. “We finally realized that the stuff we’d been buying was complete garbage,” Hone said.

    Around 2016, he decided to go into the business of growing research-grade TMDs. He recruited a postdoc, Daniel Rhodes, with experience growing crystals by melting powders of raw materials at extremely high temperatures and then cooling them at a glacial pace. “It’s like growing rock candy from sugar in water,” Hone explained. The new process took a month, compared to a few days for commercial methods. But it produced TMD crystals hundreds to thousands of times better than the ones for sale in chemical catalogs.

    Before Shan and Mak could take advantage of Hone’s increasingly pristine crystals, they faced the unglamorous task of figuring out how to work with microscopic flakes that don’t like to accept electrons. To pump in electrons (the basis of the transport technique Mak had picked up as a postdoc), the couple obsessed over countless details: which type of metal to use for the electrode, how far from the TMD to place it, even which chemicals to use to clean the contacts. Trying out the endless ways of setting up electrodes was slow and laborious — “a time-consuming process of refining this or refining that bit by bit,” Mak said.

    They also spent years figuring out how to lift and stack the microscopic flakes, which measure just tenths of millionths of a meter across. With this ability, plus Hone’s crystals and improved electrical contacts, everything came together in 2018. The couple moved to Ithaca, New York, to take new positions at Cornell, and a cascade of pioneering results came spilling out of their lab.

    Breakthroughs at Cornell

    “Today, everything is hard to pick up for some reason,” said Zhengchao Xia, a graduate student in Mak and Shan’s group, as the dark silhouette of a boron nitride flake threatened to peel off and fall back to the silicon surface below. The Madagascar-shaped sheet clung feebly to a hunk of graphite resembling Saudi Arabia, much as paper might cling to the crackling surface of a recently rubbed balloon. The graphite, in turn, was stuck to a gooey dewdrop of plastic attached to a glass slide. Xia used a computer interface to direct a motorized stand gripping the slide. Like an arcade-goer might maneuver a claw machine with a joystick, she gingerly lifted the stack into the air at a rate of one-fifth of a millionth of a meter per mouse click, staring intently at the computer monitor to see if she had successfully nabbed the boron nitride flake.

    She had. With a few more clicks the two-layer stack came free, and Xia moved swiftly but deliberately to deposit the flakes onto a third material embedded with sprawling metal electrodes. With a few more clicks she heated the surface, melting the slide’s plastic adhesive before either of us could sneeze the microscopic device away.

    “I always have this nightmare that it just disappears,” she said.

    5
    6
    Zhengchao Xia, a graduate student in Mak and Shan’s group, uses a motorized positioning stage to stack layers of material into a new 2D device.

    From start to finish, it had taken Xia more than an hour to assemble the bottom half of a simple device — the equivalent of an open-faced PB&J. She showed me another stack she had recently put together and rattled off a few of the ingredients, which included the TMDs tungsten diselenide and moly ditelluride. One of dozens of microscopic sandwiches she has constructed and studied over the last year, this Dagwood of a device had a whopping 10 layers and took several hours to assemble.

    This stacking of 2D materials, which is also done in labs at Columbia, the Massachusetts Institute of Technology, Berkeley, Harvard and other institutions, represents the realization of a long-held dream of condensed matter physicists. No longer are researchers restricted to materials found in the ground or grown slowly in a lab. Now they can play with the atomic equivalent of Lego bricks, snapping together sheets to build bespoke structures with desired properties. When it comes to assembling TMD structures, few have gone as far as the Cornell group.

    Mak and Shan’s first major discovery at Cornell concerned excitons, the strongly bound electron-hole pairs they had seen in TMDs back in 2014. Excitons intrigue physicists because these “quasiparticles” may offer a roundabout way to achieve a perennial goal of condensed matter physics: room-temperature superconductivity.

    Excitons play by the same funky rules as electron-electron pairs; these electron-hole pairs, too, become bosons, which lets them “condense” into a shared quantum state known as a Bose-Einstein condensate. This coherent horde of quasiparticles can display quantum traits such as superfluidity, the ability to flow with no resistance. (When a superfluid carries electric current, it superconducts.)

    But unlike repulsive electrons, electrons and holes love to couple up. Researchers say this potentially makes their glue stronger. The challenges to exciton-based superconductivity lie in keeping the electron from filling the hole, and getting the electrically neutral pairs to flow in a current — all in as warm a room as possible. So far, Mak and Shan have solved the first problem and have a plan to tackle the second.

    Clouds of atoms can be coaxed into forming condensates by chilling them to a hair above absolute zero with powerful lasers. But theorists have long suspected that condensates of excitons could form at higher temperatures. The Cornell group made this idea a reality with their stackable TMDs. Using a two-layer sandwich, they put extra electrons in the top layer and removed electrons from the bottom, leaving holes. The electrons and holes paired up, making excitons that are long-lived because the electrons have trouble jumping to the opposite layer to neutralize their partners. In October 2019, the group reported signs [Nature (below)] of an exciton condensate at a balmy 100 kelvins. In this setup, the excitons persisted for tens of nanoseconds, a lifetime for this type of quasiparticle. In the fall of 2021 [Nature (below)] , the group described an improved apparatus where excitons seem to last for milliseconds, which Mak called “practically forever.”

    8
    9
    Researchers rip Scotch tape off a 3D crystal to create 2D sheets (left). They then stack these layers and attach electrodes. A microscopic image of one such device appears on a computer monitor (right).
    Sasha Maslov for Quanta Magazine

    The team is now pursuing a scheme [Nature Physics (below)] concocted by theorists in 2008 for creating an exciton current. Allan MacDonald, a prominent condensed matter theorist at the University of Texas, Austin, and his graduate student Jung-Jung Su proposed making neutral excitons flow by applying an electric field oriented in a way that encourages both electrons and holes to move in the same direction. To pull it off in the lab, the Cornell group must once again grapple with their perennial enemy, electrical contacts. In this case, they have to attach multiple sets of electrodes to the TMD layers, some to manufacture the excitons and others to move them.

    Shan and Mak believe they are on track to get excitons flowing at up to 100 kelvins soon. That’s a frigid room for a person (−173 degrees Celsius or −280 degrees Fahrenheit), but it’s a huge leap from the nanokelvin conditions that most bosonic condensates need.

    “That will be by itself a nice achievement,” Mak said with a sly smile, “to warm up the temperature by a billion times.”

    Magical Moiré Materials

    In 2018, while the Cornell lab ramped up their TMD experiments, another graphene surprise launched a second 2D materials revolution. Pablo Jarillo-Herrero, a researcher at MIT and another Columbia alum, announced that twisting one layer of graphene with respect to the layer below created a magical new 2D material. The secret was to drop the upper layer such that its hexagons landed with a slight “twist,” so that they were rotated exactly 1.1 degrees against the hexagons below. This angle misalignment causes an offset between atoms that grows and shrinks as you move across a material, generating a repeating pattern of large “supercells” known as a moiré superlattice. MacDonald and a colleague had calculated in 2011 [PNAS (below)] that at the “magic angle” of 1.1 degrees, the unique crystal structure of the superlattice would compel graphene’s electrons to slow and sense the repulsion of their neighbors.

    9
    Merrill Sherman/Quanta Magazine

    When electrons become aware of each other, weird things happen. In normal insulators, conductors and semiconductors, electrons are thought to interact only with the lattice of atoms; they race around too quickly to notice each other. But slowed to a crawl, electrons can jostle each other and collectively assume an assortment of exotic quantum states. Jarillo-Herrero’s experiments demonstrated that, for poorly understood reasons, this electron-to-electron communication in twisted, magic-angle graphene gives rise to an especially strong form of superconductivity.

    The graphene moiré superlattice also introduced researchers to a radical new way of controlling electrons. In the superlattice, electrons become oblivious to the individual atoms and experience the supercells themselves as if they were giant atoms. This makes it easy to populate the supercells with enough electrons to form collective quantum states. Using an electric field to dial up or down the average number of electrons per supercell, Jarillo-Herrero’s group was able to make their twisted bilayer graphene device serve as a superconductor, act as an insulator, or display a raft of other, stranger electron behaviors.

    Physicists around the world rushed into the nascent field of “twistronics.” But many have found that twisting is tough. Atoms have no reason to fall neatly into the “magic” 1.1-degree misalignment, so sheets wrinkle in ways that completely change their properties. Xia, the Cornell graduate student, said she has a bunch of friends at other universities working with twisted devices. Creating a working device typically takes them dozens of tries. And even then, each device behaves differently, so specific experiments are almost impossible to repeat.

    TMDs present a far easier way to create moiré superlattices. Because different TMDs have hexagonal lattices of different sizes, stacking a lattice of slightly larger hexagons over a smaller lattice creates a moiré pattern just the way angle misalignment does. In this case, because there is no rotation between the layers, the stack is more likely to snap into place and stay still. When Xia sets out to create a TMD moiré device, she said, she generally succeeds four times out of five.

    TMD moiré materials make ideal playgrounds for exploring electron interactions. Because the materials are semiconductors, their electrons get heavy as they slog through the materials, unlike the frenetic electrons in graphene. And the gigantic moiré cells slow them down further: Whereas electrons often move between atoms by “tunneling,” a quantum mechanical behavior akin to teleportation, tunneling rarely happens in a moiré lattice, since supercells sit roughly 100 times further apart than the atoms inside them. The distance helps the electrons settle down and gives them a chance to know their neighbors.

    Shan and Mak’s friendly rival, Feng Wang, was one of the first to recognize the potential of TMD moiré superlattices. Back-of-the-envelope calculations suggested that these materials should give rise to one of the simplest ways electrons can organize — a state known as a Wigner crystal, where mutual repulsion locks lethargic electrons into place. Wang’s team saw signs of such states [Nature (below)] in 2020 and published the first image [Nature (below)] of electrons holding each other at arm’s length in Nature in 2021. By then, word of Wang’s TMD moiré activities had already spread through the tightknit 2D physics community, and the Cornell TMD factory was churning out TMD moiré devices of their own. Shan and Mak also reported evidence for Wigner crystals in TMD superlattices in 2020 and discovered within months that electrons in their devices could crystallize in almost two dozen different Wigner crystal patterns [Nature (below)].

    At the same time, the Cornell group was also crafting TMD moiré materials into a power tool. MacDonald and collaborators had predicted [Physical Review Letters (below)] in 2018 that these devices have the right combination of technical features to make them perfectly represent one of the most important toy models in condensed matter physics. The Hubbard model, as it’s called, is a theorized system used to understand a wide variety of electron behaviors. Independently proposed [Nature Physics (below)] by Martin Gutzwiller, Junjiro Kanamori and John Hubbard in 1963, the model is physicists’ best attempt to strip the practically infinite variety of crystalline lattices down to their most essential features. Picture a grid of atoms hosting electrons. The Hubbard model assumes that each electron feels two competing forces: It wants to move by tunneling to neighboring atoms, but it’s also repulsed by its neighbors, which makes it want to stay where it is. Different behaviors arise depending on which desire is strongest. The only problem with the Hubbard model is that in all but the simplest case — a 1D string of atoms — it is mathematically unsolvable.

    According to MacDonald and colleagues, TMD moiré materials could act as “simulators” of the Hubbard model, potentially solving some of the field’s deepest mysteries, such as the nature of the glue that binds electrons into superconducting pairs in cuprates. Instead of struggling with an impossible equation, researchers could set electrons loose in a TMD sandwich and see what they did. “We can write down this model, but it’s very difficult to answer lots of important questions,” MacDonald said. “Now we can do it just by doing an experiment. That’s really groundbreaking.”


    Merrill Sherman/Quanta Magazine

    To build their Hubbard model simulator, Shan and Mak stacked layers of tungsten diselenide and tungsten sulfide to create a moiré superlattice, and they attached electrodes to dial up or down an electric field passing through the TMD sandwich. The electric field controlled how many electrons would fill each supercell. Since the cells act like giant atoms, going from one electron to two electrons per supercell was like transforming a lattice of hydrogen atoms into a lattice of helium atoms. In their initial Hubbard model publication in Nature in March 2020 [Nature (below)], they reported simulating atoms with up to two electrons; today, they can go up to eight. In some sense, they had realized the ancient aim of turning lead into gold. “It’s like tuning chemistry,” Mak said, “going through the periodic table.” In principle, they can even conjure up a grid of fictitious atoms with, say, 1.38 electrons each.

    Next, the group looked to the hearts of the artificial atoms. With more electrodes, they could control the supercells’ “potential” by making changes akin to adding positive protons to the centers of the giant synthetic atoms. The more charge a nucleus has, the harder it is for electrons to tunnel away, so this electric field let them raise and lower the hopping tendency.

    Mak and Shan’s control of the giant atoms — and therefore the Hubbard model — was complete. The TMD moiré system lets them summon a grid of ersatz atoms, even ones that don’t exist in nature, and smoothly transform them as they wish. It’s a power that, even to other researchers in the field, borders on magical. “If I were to single out their most exciting and impressive effort, that’s the one,” Kim said.

    The Cornell group quickly used their designer atoms to settle a 70-year-old debate. The question was: What if you could take an insulator and tweak its atoms to turn it into a conducting metal? Would the changeover happen gradually or abruptly?

    With their moiré alchemy, Shan and Mak carried out the thought experiment in their lab. First they simulated heavy atoms, which trapped electrons so that the TMD superlattice acted like an insulator. Then they shrank the atoms, weakening the trap until electrons became able to hop to freedom, letting the superlattice become a conducting metal. By observing a gradually falling electrical resistance as the superlattice acted increasingly like a metal, they showed that the transition is not abrupt. This finding, which they announced in Nature [Nature] last year, opens up the possibility that the superlattice’s electrons may be able to achieve a long-sought type of fluidity known as a quantum spin liquid. “That may be the most interesting problem one can tackle,” Mak said.

    Almost at the same time, the couple lucked into what some physicists consider their most significant discovery yet. “It was actually a total accident,” Mak said. “Nobody expected it.”

    When they started their Hubbard simulator research, the researchers used TMD sandwiches in which the hexagons on the two layers are aligned, with transition metals atop transition metals and chalcogenides atop chalcogenides. (That’s when they discovered the gradual insulator-to-metal transition.) Then, serendipitously, they happened to repeat the experiment with devices in which the top layer had been stacked backward.

    As before, the resistance started falling as electrons began to hop. But then it plunged abruptly, going so low that the researchers wondered if the moiré had begun to superconduct. Exploring further, though, they measured a rare pattern of resistance [Nature(below)]known as the quantum anomalous Hall effect — proof that something even weirder was going on. The effect indicated that the crystal structure of the device was compelling electrons along the edge of the material to act differently from those in the center. In the middle of the device, electrons were trapped in an insulating state. But around the perimeter, they flowed in one direction — explaining the super-low resistance. By accident, the researchers had created an extremely unusual and fragile type of matter known as a Chern insulator.


    Merrill Sherman/Quanta Magazine

    The quantum anomalous hall effect, first observed in 2013 [Science (below)], usually falls apart if the temperature rises above a few hundredths of a kelvin. In 2019, Young’s group in Santa Barbara had seen it in a one-off twisted graphene sandwich at around 5 kelvins. Now Shan and Mak had achieved the effect at nearly the same temperature, but in a no-twist TMD device that anyone can re-create. “Ours was a higher temperature, but I’ll take theirs any day because they can do it 10 times in a row,” Young said. That means you can understand it “and use it to actually do something.”

    Mak and Shan believe that, with some fiddling, they can use TMD moiré materials to build Chern insulators that survive to 50 or 100 kelvin. If they’re successful, the work could lead to another way to get current flowing with no resistance — at least for tiny “nanowires,” which they may even be able to switch on and off at specific places within a device.

    Exploration in Flatland

    Even as the landmark results pile up, the couple shows no signs of slowing down. On the day I visited, Mak looked on as students tinkered with a towering dilution refrigerator that would let them chill their devices to temperatures a thousand times colder than what they’ve worked with so far. There’s been so much physics to discover at “warmer” conditions that the group hasn’t had a chance to thoroughly search the deeper cryogenic realm for signs of superconductivity. If the super fridge lets the TMDs superconduct, that will answer yet another question, showing that a form of magnetism intrinsic to cuprates (but absent from TMDs) is not an essential ingredient of the electron-binding glue. “That’s like killing one of the important components that theorists really wanted to kill for a long time,” Mak said.

    He and Shan and their group haven’t even begun to experiment with some of the funkier TMDs. After spending years inventing the equipment needed to move around the continent of 2D materials, they’re finally gearing up to venture beyond the moly disulfide beachhead they landed on back in 2010.

    The two researchers attribute their success to a culture of cooperation that they absorbed at Columbia. The initial collaboration with Hone that introduced them to moly disulfide, they say, was just one of the many opportunities they enjoyed because they were free to follow their curiosity. “We didn’t have to discuss” their plans with Heinz, the head of their lab, Shan said. “We talked to people from other groups. We did the experiments. We even wrapped things up.”

    Today they foster a similarly relaxed environment at Cornell, where they oversee a couple dozen postdocs, visiting researchers and students, all of whom are largely free to do their own thing. “Students are very smart and have good ideas,” Mak said. “Sometimes you don’t want to interfere.”

    Their marriage also makes their lab unique. The two have learned to lean into their personal strengths. Besides an abundance of creativity as an experimentalist, Shan possesses a careful discipline that makes her a good manager; as the three of us talked, she frequently nudged “Professor Fai” back on track when his enthusiasm for physics pushed him too deep into technicalities. Mak, for his part, enjoys toiling alongside the early-career researchers, both inside and outside the lab. He recently started rock climbing with the group. “It seems like their lab is their family,” said Young. Shan and Mak told me they achieve more together than they could alone. “One plus one is more than two,” Mak said.

    The devices they’re building may also stack up to be more than the sum of their parts. As researchers join TMD sheets together to create excitons and moiré superlattices, they speculate about how the new ways of domesticating electrons might supercharge technology. Even if pocket-ready superconductivity remains elusive, Bose-Einstein condensates could lead to ultra-sensitive quantum sensors, and better control of Chern-like insulators could enable powerful quantum computers. And those are just the obvious ideas. Incremental improvements in materials science often add up to radical applications few saw coming. The researchers who developed the transistor, for instance, would have struggled to predict smartphones powered by billions of microscopic switches stuffed into a chip the size of a fingernail. And the scientists who endeavored to fashion glass fibers that could carry light across their lab bench could not have foreseen that 10,000-kilometer undersea optical fibers would someday link continents. Two-dimensional materials may evolve in similarly unpredictable directions. “A really new materials platform generates its own applications as opposed to displacing existing materials,” said Heinz.

    While driving me to the Ithaca bus stop, Shan and Mak told me about a recent (and rare) vacation they took to Banff, Canada, where they once again displayed their knack for stumbling onto surprises through a blend of effort and luck. They had spent days trying — in vain — to spot a bear. Then, at the end of the trip, on their way to the airport, they stopped to stretch their legs at a botanical reserve and found themselves face to face with a black bear.

    Similarly, with condensed matter physics, their approach is to wander around together in a new landscape and see what shows up. “We don’t have much theoretical guidance, but we just fool around and play with experiments,” Mak said. “It can fail, but sometimes you can bump into something very unexpected.”

    Science papers:
    Zeitschrift für Physik B Condensed Matter
    Nature Materials
    Science
    Nano Letters
    Nature Reviews Materials
    Science
    Physical Review Letters
    Nature
    Nature
    Nature Physics
    PNAS
    Nature
    Nature
    Nature
    Physical Review Letters
    Nature Physics
    Nature
    Nature
    Nature
    Science

    See the full article here .


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    Formerly known as Simons Science News, Quanta Magazine is an editorially independent online publication launched by The Simons Foundation to enhance public understanding of science. Why Quanta? Albert Einstein called photons “quanta of light.” Our goal is to “illuminate science.” At Quanta Magazine, scientific accuracy is every bit as important as telling a good story. All of our articles are meticulously researched, reported, edited, copy-edited and fact-checked.

     
  • richardmitnick 10:26 am on July 13, 2022 Permalink | Reply
    Tags: "A proof of odd-parity superconductivity", , “Even parity” vs “Odd parity”, , Superconductivity   

    From MPG Institute for Chemical Physics of Solids [MPG institut für Chemische Physik fester Stoffe] (DE): “A proof of odd-parity superconductivity” 

    From The MPG Institute for Chemical Physics of Solids [MPG institut für Chemische Physik fester Stoffe] (DE)

    July 05, 2022

    Javier Landaeta
    Post-doctoral research scientist
    +49 351 4646-3125
    Javier.Landaeta@cpfs.mpg.de

    Elena Hassinger
    Max Planck Research Group leader
    +49 351 4646-3229
    Elena.Hassinger@cpfs.mpg.de

    Observations reveal the angle dependence of the magnetic field needed to suppress superconductivity in CeRh2As2. Uniquely, the behavior of “odd parity” superconductors is revealed.

    1
    Angle dependence of the superconducting critical fields in CeRh2As2 determined by ac-susceptibility, magnetic torque and specific heat. The observed behavior is in excellent agreement with the expected one of even and odd-parity superconductivity. © PRX.

    Superconductivity is a fascinating state of matter in which an electrical current can flow without any resistance. Usually, it can exist in two forms. One is destroyed easily with a magnetic field and has “even parity”, i.e. it has a point symmetric wave function with respect to an inversion point, and one which is stable in magnetic fields applied in certain directions and has “odd parity”, i.e. it has an antisymmetric wave function. Consequently, the latter should present a characteristic angle dependence of the critical field where superconductivity disappears. But odd-parity superconductivity is rare in nature; only a few materials support this state, and in none of them has the expected angle dependence been observed.

    CeRh2As2 was recently found to exhibit two superconducting states: A low-field state changes into a high-field state at 4 T when a magnetic field is applied along one axis. For varying field directions, we measured the specific heat, magnetic susceptibility, and magnetic torque of this material to obtain the angle dependence of the critical fields. We find that the high-field state quickly disappears when the magnetic field is turned away from the initial axis. These results are in excellent agreement with our model identifying the two states with even- and odd-parity states.

    CeRh2As2 presents an extraordinary opportunity to investigate odd-parity superconductivity further. It also allows for testing mechanisms for a transition between two superconducting states, and especially their relation to spin-orbit coupling, multiband physics, and additional ordered states occurring in this material.

    In a new publication in Physical Review X, the group by Elena Hassinger and collaborators show that the angle dependence in the superconductor CeRh2As2 is exactly that expected of an odd-parity state.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    The MPG Institute for Chemical Physics of Solids [MPG institut für Chemische Physik fester Stoffe] (DE) is a research institute of the MPG Society. Located in Dresden, the institute primarily conducts basic research in the natural sciences in the fields of physics and chemistry.

    Mission

    The MPI CPfS conducts research on modern solid state chemistry and physics. Key open questions include “understanding the interplay of topology and symmetry in modern materials, maximising the level of control in material synthesis, understanding the nature of the chemical bond in intermetallic compounds and studying giant response functions at the borderline of standard metallic and superconducting behaviour”.

    Departments of the Institute

    Physics of Correlated Matter
    Physics of Quantum Materials
    Chemical Metals Science
    Solid State Chemistry
    Research group: Physics of Unconventional Metals and Superconductors
    Research group: Nanostructured Quantum Matter Group
    Research group: Spin3D: Three-dimensional magnetic systems
    Research group:
    Quantum Information for Quantum Materials

    The MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] is a formally independent non-governmental and non-profit association of German research institutes founded in 1911 as the Kaiser Wilhelm Society and renamed the Max Planck Society in 1948 in honor of its former president, theoretical physicist Max Planck. The society is funded by the federal and state governments of Germany as well as other sources.

    According to its primary goal, the MPG Society supports fundamental research in the natural, life and social sciences, the arts and humanities in its 83 (as of January 2014) MPG Institutes. The society has a total staff of approximately 17,000 permanent employees, including 5,470 scientists, plus around 4,600 non-tenured scientists and guests. Society budget for 2015 was about €1.7 billion.

    The MPG Institutes focus on excellence in research. The MPG Society has a world-leading reputation as a science and technology research organization, with 33 Nobel Prizes awarded to their scientists, and is generally regarded as the foremost basic research organization in Europe and the world. In 2013, the Nature Publishing Index placed the MPG institutes fifth worldwide in terms of research published in Nature journals (after Harvard University, The Massachusetts Institute of Technology, Stanford University and The National Institutes of Health). In terms of total research volume (unweighted by citations or impact), the Max Planck Society is only outranked by The Chinese Academy of Sciences [中国科学院](CN), The Russian Academy of Sciences [Росси́йская акаде́мия нау́к](RU) and Harvard University. The Thomson Reuters-Science Watch website placed the MPG Society as the second leading research organization worldwide following Harvard University, in terms of the impact of the produced research over science fields.

    The MPG Society and its predecessor Kaiser Wilhelm Society hosted several renowned scientists in their fields, including Otto Hahn, Werner Heisenberg, and Albert Einstein.

    History

    The organization was established in 1911 as the Kaiser Wilhelm Society, or Kaiser-Wilhelm-Gesellschaft (KWG), a non-governmental research organization named for the then German emperor. The KWG was one of the world’s leading research organizations; its board of directors included scientists like Walther Bothe, Peter Debye, Albert Einstein, and Fritz Haber. In 1946, Otto Hahn assumed the position of President of KWG, and in 1948, the society was renamed the Max Planck Society (MPG) after its former President (1930–37) Max Planck, who died in 1947.

    The MPG Society has a world-leading reputation as a science and technology research organization. In 2006, the Times Higher Education Supplement rankings of non-university research institutions (based on international peer review by academics) placed the MPG Society as No.1 in the world for science research, and No.3 in technology research (behind AT&T Corporation and The DOE’s Argonne National Laboratory.

    The domain mpg.de attracted at least 1.7 million visitors annually by 2008 according to a Compete.com study.

    MPG Institutes and research groups

    The MPG Society consists of over 80 research institutes. In addition, the society funds a number of Max Planck Research Groups (MPRG) and International Max Planck Research Schools (IMPRS). The purpose of establishing independent research groups at various universities is to strengthen the required networking between universities and institutes of the Max Planck Society.
    The research units are primarily located across Europe with a few in South Korea and the U.S. In 2007, the Society established its first non-European centre, with an institute on the Jupiter campus of Florida Atlantic University (US) focusing on neuroscience.
    The MPG Institutes operate independently from, though in close cooperation with, the universities, and focus on innovative research which does not fit into the university structure due to their interdisciplinary or transdisciplinary nature or which require resources that cannot be met by the state universities.

    Internally, MPG Institutes are organized into research departments headed by directors such that each MPI has several directors, a position roughly comparable to anything from full professor to department head at a university. Other core members include Junior and Senior Research Fellows.

    In addition, there are several associated institutes:

    International Max Planck Research Schools

    Together with the Association of Universities and other Education Institutions in Germany, the Max Planck Society established numerous International Max Planck Research Schools (IMPRS) to promote junior scientists:

    • Cologne Graduate School of Ageing Research, Cologne
    • International Max Planck Research School for Intelligent Systems, at the Max Planck Institute for Intelligent Systems located in Tübingen and Stuttgart
    • International Max Planck Research School on Adapting Behavior in a Fundamentally Uncertain World (Uncertainty School), at the Max Planck Institutes for Economics, for Human Development, and/or Research on Collective Goods
    • International Max Planck Research School for Analysis, Design and Optimization in Chemical and Biochemical Process Engineering, Magdeburg
    • International Max Planck Research School for Astronomy and Cosmic Physics, Heidelberg at the MPI for Astronomy
    • International Max Planck Research School for Astrophysics, Garching at the MPI for Astrophysics
    • International Max Planck Research School for Complex Surfaces in Material Sciences, Berlin
    • International Max Planck Research School for Computer Science, Saarbrücken
    • International Max Planck Research School for Earth System Modeling, Hamburg
    • International Max Planck Research School for Elementary Particle Physics, Munich, at the MPI for Physics
    • International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Marburg at the Max Planck Institute for Terrestrial Microbiology
    • International Max Planck Research School for Evolutionary Biology, Plön at the Max Planck Institute for Evolutionary Biology
    • International Max Planck Research School “From Molecules to Organisms”, Tübingen at the Max Planck Institute for Developmental Biology
    • International Max Planck Research School for Global Biogeochemical Cycles, Jena at the Max Planck Institute for Biogeochemistry
    • International Max Planck Research School on Gravitational Wave Astronomy, Hannover and Potsdam MPI for Gravitational Physics
    • International Max Planck Research School for Heart and Lung Research, Bad Nauheim at the Max Planck Institute for Heart and Lung Research
    • International Max Planck Research School for Infectious Diseases and Immunity, Berlin at the Max Planck Institute for Infection Biology
    • International Max Planck Research School for Language Sciences, Nijmegen
    • International Max Planck Research School for Neurosciences, Göttingen
    • International Max Planck Research School for Cognitive and Systems Neuroscience, Tübingen
    • International Max Planck Research School for Marine Microbiology (MarMic), joint program of the Max Planck Institute for Marine Microbiology in Bremen, the University of Bremen, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, and the Jacobs University Bremen
    • International Max Planck Research School for Maritime Affairs, Hamburg
    • International Max Planck Research School for Molecular and Cellular Biology, Freiburg
    • International Max Planck Research School for Molecular and Cellular Life Sciences, Munich
    • International Max Planck Research School for Molecular Biology, Göttingen
    • International Max Planck Research School for Molecular Cell Biology and Bioengineering, Dresden
    • International Max Planck Research School Molecular Biomedicine, program combined with the ‘Graduate Programm Cell Dynamics And Disease’ at the University of Münster and the Max Planck Institute for Molecular Biomedicine
    • International Max Planck Research School on Multiscale Bio-Systems, Potsdam
    • International Max Planck Research School for Organismal Biology, at the University of Konstanz and the Max Planck Institute for Ornithology
    • International Max Planck Research School on Reactive Structure Analysis for Chemical Reactions (IMPRS RECHARGE), Mülheim an der Ruhr, at the Max Planck Institute for Chemical Energy Conversion
    • International Max Planck Research School for Science and Technology of Nano-Systems, Halle at Max Planck Institute of Microstructure Physics
    • International Max Planck Research School for Solar System Science at the University of Göttingen hosted by MPI for Solar System Research
    • International Max Planck Research School for Astronomy and Astrophysics, Bonn, at the MPI for Radio Astronomy (formerly the International Max Planck Research School for Radio and Infrared Astronomy)
    • International Max Planck Research School for the Social and Political Constitution of the Economy, Cologne
    • International Max Planck Research School for Surface and Interface Engineering in Advanced Materials, Düsseldorf at Max Planck Institute for Iron Research GmbH
    • International Max Planck Research School for Ultrafast Imaging and Structural Dynamics, Hamburg

    Max Planck Schools

    • Max Planck School of Cognition
    • Max Planck School Matter to Life
    • Max Planck School of Photonics

    Max Planck Center

    • The Max Planck Centre for Attosecond Science (MPC-AS), POSTECH Pohang
    • The Max Planck POSTECH Center for Complex Phase Materials, POSTECH Pohang

    Max Planck Institutes

    Among others:
    • Max Planck Institute for Neurobiology of Behavior – caesar, Bonn
    • Max Planck Institute for Aeronomics in Katlenburg-Lindau was renamed to Max Planck Institute for Solar System Research in 2004;
    • Max Planck Institute for Biology in Tübingen was closed in 2005;
    • Max Planck Institute for Cell Biology in Ladenburg b. Heidelberg was closed in 2003;
    • Max Planck Institute for Economics in Jena was renamed to the Max Planck Institute for the Science of Human History in 2014;
    • Max Planck Institute for Ionospheric Research in Katlenburg-Lindau was renamed to Max Planck Institute for Aeronomics in 1958;
    • Max Planck Institute for Metals Research, Stuttgart
    • Max Planck Institute of Oceanic Biology in Wilhelmshaven was renamed to Max Planck Institute of Cell Biology in 1968 and moved to Ladenburg 1977;
    • Max Planck Institute for Psychological Research in Munich merged into the Max Planck Institute for Human Cognitive and Brain Sciences in 2004;
    • Max Planck Institute for Protein and Leather Research in Regensburg moved to Munich 1957 and was united with the Max Planck Institute for Biochemistry in 1977;
    • Max Planck Institute for Virus Research in Tübingen was renamed as Max Planck Institute for Developmental Biology in 1985;
    • Max Planck Institute for the Study of the Scientific-Technical World in Starnberg (from 1970 until 1981 (closed)) directed by Carl Friedrich von Weizsäcker and Jürgen Habermas.
    • Max Planck Institute for Behavioral Physiology
    • Max Planck Institute of Experimental Endocrinology
    • Max Planck Institute for Foreign and International Social Law
    • Max Planck Institute for Physics and Astrophysics
    • Max Planck Research Unit for Enzymology of Protein Folding
    • Max Planck Institute for Biology of Ageing

     
  • richardmitnick 9:17 am on July 9, 2022 Permalink | Reply
    Tags: "Magic-angle graphene", "Physicists discover a 'family' of robust and superconducting graphene structures", , Flat band structure, Four and five graphene layers can be twisted and stacked at new magic angles to elicit robust superconductivity at low temperatures., Graphene is a single-atom-thin material that can be exfoliated from the same graphite that is found in pencil lead., , Superconductivity, The findings could serve as a blueprint for designing practical room-temperature superconductors., The magic-angle graphene system is now a legitimate "family" beyond a couple of systems.,   

    From The Massachusetts Institute of Technology: “Physicists discover a ‘family’ of robust and superconducting graphene structures” 

    From The Massachusetts Institute of Technology

    July 8, 2022
    Jennifer Chu

    1
    An illustration showing superconducting Cooper pairs in magic-angle multilayer graphene family. The adjacent layers are twisted in an alternating fashion. Credit: Ella Maru Studio.

    2
    MIT physicists have established twisted graphene as a new “family” of robust superconductors, each member consisting of alternating graphene layers, stacked at precise angles. Courtesy of the researchers.

    When it comes to graphene, it appears that superconductivity runs in the family.

    Graphene is a single-atom-thin material that can be exfoliated from the same graphite that is found in pencil lead. The ultrathin material is made entirely from carbon atoms that are arranged in a simple hexagonal pattern, similar to that of chicken wire. Since its isolation in 2004, graphene has been found to embody numerous remarkable properties in its single-layer form.

    In 2018, MIT researchers found that if two graphene layers are stacked at a very specific “magic” angle, the twisted bilayer structure could exhibit robust superconductivity, a widely sought material state in which an electrical current can flow through with zero energy loss. Recently, the same group found a similar superconductive state exists in twisted trilayer graphene — a structure made from three graphene layers stacked at a precise, new magic angle.

    Now the team reports that — you guessed it — four and five graphene layers can be twisted and stacked at new magic angles to elicit robust superconductivity at low temperatures. This latest discovery, published this week in Nature Materials, establishes the various twisted and stacked configurations of graphene as the first known “family” of multilayer magic-angle superconductors. The team also identified similarities and differences between graphene family members.

    The findings could serve as a blueprint for designing practical room-temperature superconductors. If the properties among family members could be replicated in other, naturally conductive materials, they could be harnessed, for instance, to deliver electricity without dissipation or build magnetically levitating trains that run without friction.

    “The magic-angle graphene system is now a legitimate “family” beyond a couple of systems,” says lead author Jeong Min (Jane) Park, a graduate student in MIT’s Department of Physics. “Having this family is particularly meaningful because it provides a way to design robust superconductors.”

    Park’s MIT co-authors include Yuan Cao, Li-Qiao Xia, Shuwen Sun, and Pablo Jarillo-Herrero, the Cecil and Ida Green Professor of Physics, along with Kenji Watanabe and Takashi Taniguchi of the National Institute for Materials Science in Tsukuba, Japan.

    “No limit”

    Jarillo-Herrero’s group was the first to discover “magic-angle graphene”, in the form of a bilayer structure of two graphene sheets placed one atop the other and slightly offset at a precise angle of 1.1 degrees. This twisted configuration, known as a moiré superlattice, transformed the material into a strong and persistent superconductor at ultralow temperatures.

    The researchers also found that the material exhibited a type of electronic structure known as a “flat band,” in which the material’s electrons have the same energy, regardless of their momentum. In this flat band state, and at ultracold temperatures, the normally frenetic electrons collectively slow down enough to pair up in what are known as Cooper pairs — essential ingredients of superconductivity that can flow through the material without resistance.

    While the researchers observed that twisted bilayer graphene exhibited both superconductivity and a flat band structure, it wasn’t clear whether the former arose from the latter.

    “There was no proof a flat band structure led to superconductivity,” Park says. “Other groups since then have produced other twisted structures from other materials that have some flattish band, but they didn’t really have robust superconductivity. So we wondered: Could we produce another flat band superconducting device?”

    As they considered this question, a group from Harvard University derived calculations that confirmed mathematically that three graphene layers, twisted at 1.6 degrees, would exhibit also flat bands, and suggested they may superconduct. They went on to show there should be no limit to the number of graphene layers that exhibit superconductivity, if stacked and twisted in just the right way, at angles they also predicted. Finally, they proved they could mathematically relate every multilayer structure to a common flat band structure — strong proof that a flat band may lead to robust superconductivity.

    “They worked out there may be this entire hierarchy of graphene structures, to infinite layers, that might correspond to a similar mathematical expression for a flat band structure,” Park says.

    Shortly after that work, Jarillo-Herrero’s group found that, indeed, superconductivity and a flat band emerged in twisted trilayer graphene — three graphene sheets, stacked like a cheese sandwich, the middle cheese layer shifted by 1.6 degrees with respect to the sandwiched outer layers. But the trilayer structure also showed subtle differences compared to its bilayer counterpart.

    “That made us ask, where do these two structures fit in terms of the whole class of materials, and are they from the same family?” Park says.

    An unconventional family

    In the current study, the team looked to level up the number of graphene layers. They fabricated two new structures, made from four and five graphene layers, respectively. Each structure is stacked alternately, similar to the shifted cheese sandwich of twisted trilayer graphene.

    The team kept the structures in a refrigerator below 1 kelvin (about -273 degrees Celsius), ran electrical current through each structure, and measured the output under various conditions, similar to tests for their bilayer and trilayer systems.

    Overall, they found that both four- and five-layer twisted graphene also exhibit robust superconductivity and a flat band. The structures also shared other similarities with their three-layer counterpart, such as their response under a magnetic field of varying strength, angle, and orientation.

    These experiments showed that twisted graphene structures could be considered a new family, or class of common superconducting materials. The experiments also suggested there may be a black sheep in the family: The original twisted bilayer structure, while sharing key properties, also showed subtle differences from its siblings. For instance, the group’s previous experiments showed the structure’s superconductivity broke down under lower magnetic fields and was more uneven as the field rotated, compared to its multilayer siblings.

    The team carried out simulations of each structure type, seeking an explanation for the differences between family members. They concluded that the fact that twisted bilayer graphene’s superconductivity dies out under certain magnetic conditions is simply because all of its physical layers exist in a “nonmirrored” form within the structure. In other words, there are no two layers in the structure that are mirror opposites of each other, whereas graphene’s multilayer siblings exhibit some sort of mirror symmetry. These findings suggest that the mechanism driving electrons to flow in a robust superconductive state is the same across the twisted graphene family.

    “That’s quite important,” Park notes. “Without knowing this, people might think bilayer graphene is more conventional compared to multilayer structures. But we show that this entire family may be unconventional, robust superconductors.”

    This research was supported, in part, by the U.S. Department of Energy, the National Science Foundation, the Air Force Office of Scientific Research, the Gordon and Betty Moore Fundation, the Ramon Areces Foundation, and the CIFAR Program on Quantum Materials.

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    The Massachusetts Institute of Technology is a private land-grant research university in Cambridge, Massachusetts. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River. The institute also encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory , the MIT Bates Research and Engineering Center , and the Haystack Observatory , as well as affiliated laboratories such as the Broad Institute of MIT and Harvard and Whitehead Institute.

    Massachusettes Institute of Technology-Haystack Observatory Westford, Massachusetts, USA, Altitude 131 m (430 ft).

    Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.

    As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with The Massachusetts Institute of Technology . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology is a member of the Association of American Universities (AAU).

    Foundation and vision

    In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.

    Rogers, a professor from the University of Virginia , wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:

    “The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”

    The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.

    Early developments

    Two days after The Massachusetts Institute of Technology was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst ). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.

    The Massachusetts Institute of Technology was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.

    The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology faculty and alumni rebuffed Harvard University president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.

    In 1916, The Massachusetts Institute of Technology administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.

    Curricular reforms

    In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities in 1934.

    Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at The Massachusetts Institute of Technology that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.

    The Massachusetts Institute of Technology‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology ‘s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, The Massachusetts Institute of Technology became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.

    These activities affected The Massachusetts Institute of Technology profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of The Massachusetts Institute of Technology between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, The Massachusetts Institute of Technology no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.

    In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and The Massachusetts Institute of Technology ‘s defense research. In this period Massachusetts Institute of Technology’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. The Massachusetts Institute of Technology ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)

    In the 1980s, there was more controversy at The Massachusetts Institute of Technology over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, The Massachusetts Institute of Technology’s research for the military has included work on robots, drones and ‘battle suits’.

    Recent history

    The Massachusetts Institute of Technology has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.

    The Massachusetts Institute of Technology was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.

    In 2001, inspired by the open source and open access movements, The Massachusetts Institute of Technology launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, The Massachusetts Institute of Technology announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology faculty adopted an open-access policy to make its scholarship publicly accessible online.

    The Massachusetts Institute of Technology has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology community with thousands of police officers from the New England region and Canada. On November 25, 2013, The Massachusetts Institute of Technology announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of The Massachusetts Institute of Technology community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.

    In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.

    The Caltech/MIT Advanced aLIGO was designed and constructed by a team of scientists from California Institute of Technology , Massachusetts Institute of Technology, and industrial contractors, and funded by the National Science Foundation .

    Caltech /MIT Advanced aLigo

    It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also a Massachusetts Institute of Technology graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.

    The mission of The Massachusetts Institute of Technology is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of The Massachusetts Institute of Technology community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

     
  • richardmitnick 7:23 pm on May 25, 2022 Permalink | Reply
    Tags: "Finding Superconductivity in Nickelates", , , , , Superconductivity,   

    From The Texas Advanced Computing Center: “Finding Superconductivity in Nickelates” 

    From The Texas Advanced Computing Center

    at

    The University of Texas-Austin

    May 25, 2022
    Aaron Dubrow

    1
    The quantum phenomena that Antia Botana studies occur at the smallest scales known and can only be probed obliquely by physical experiment. Botana uses computational simulations to make predictions, help interpret experiments, and deduce the behavior and dynamics of materials like infinite-layer nickelate.

    The study of superconductivity is littered with disappointments, dead-ends, and serendipitous discoveries, according to Antia Botana, professor of physics at Arizona State University.

    “As theorists, we generally fail in predicting new superconductors,” she said.

    However, in 2021, she experienced the highlight of her early career. Working with experimentalist Julia Mundy at Harvard University, she discovered a new superconducting material —a quintuple-layer nickelate. They reported their findings in Nature Materials in September 2021.

    “It was one of the best moments of my life,” Botana recalled. “I was flying back from Spain, and I received a message from my collaborator Julia Mundy during my layover. When I saw the resistivity drop to zero — there’s nothing better than that.”

    2
    Electronic phase diagram and structural description of the layered nickelates. A: Schematic phase diagram for the electronic phases of the cuprates (top) and nickelates (bottom). B: Crystal structures of the quintuple-layer nickelates in the Nd6Ni5O16 Ruddlesden–Popper phase (left) and Nd6Ni5O12 reduced square-planar phase (right), depicted at the same scale. [Credit: Botana et al.]

    Botana was chosen as a 2022 Sloan Research Fellow. Her research is supported by a CAREER award from the National Science Foundation (NSF).

    “Prof. Botana is one of the most influential theorists in the field of unconventional superconductivity, particularly in layered nickelates that have received tremendous attention from the materials and condensed matter physics communities,” said Serdar Ogut, Program Director in the Division of Materials Research at the National Science Foundation. “I expect that her pioneering theoretical studies, in collaboration with leading experimentalists in the US, will continue to push the boundaries, result in the discovery of new superconducting materials, and uncover fundamental mechanisms that could one day pave the way to room temperature superconductivity.”

    Superconductivity is a phenomenon that occurs when electrons form pairs rather than travelling in isolation, repulsing all magnetism, and allowing electrons to travel without losing energy. Developing room-temperature superconductors would allow loss-free electricity transmission and faster, cheaper quantum computers. Studying these materials is the domain of condensed matter theory.

    “We try to understand what are called quantum materials — materials where everything classical that we learned in our undergraduate studies falls apart and no one understands why they do the fun things they do,” Botana joked.

    She began investigating nickelates, largely, to better understand cuprates — copper-oxide based superconductors first discovered in 1986. Thirty years on, the mechanism that produces superconductivity in these materials is still hotly contested.

    Botana approaches the problem by looking at materials that look like cuprates. “Copper and nickel are right next to each other on the periodic table,” she said. “This was an obvious thing to do, so people had been looking at nickelates for a long time without success.”

    But then, in 2019, a team from Stanford discovered superconductivity in a nickelate [Nature], albeit one that had been ‘doped,’ or chemically-altered to improve its electronic characteristics. “The material that they found in 2019 is part of a larger family, which is what we want, because it lets us do comparisons to cuprates in a better way,” she said.

    Botana’s discovery in 2021 built on that foundation, using a form of undoped nickelate with a unique, square-planar, layered structure. She decided to investigate this specific form of nickelate — a rare-earth, quintuple-layer, square-planar nickelate — based on intuition.

    “Having played with many different materials for years, it’s the type of intuition that people who study electronic structure develop,” she said. “I have seen that over the years with my mentors.”

    Identifying another form of superconducting nickelate lets researchers tease out similarities and differences among nickelates and between nickelates and cuprates. So far, the more nickelates that are studied, the more like cuprates they look.

    “The phase diagram seems quite similar. The electron pairing mechanism seems to be the same,” Botana says, “but this is a question yet to be settled.”

    Conventional superconductors exhibit s-wave pairing — electrons can pair in any direction and can sit on top of each other, so the wave is a sphere. Nickelates, on the other hand, likely display d-wave pairing, meaning that the cloudlike quantum wave that describes the paired electrons is shaped like a four-leaf clover. Another key difference is how strongly oxygen and transition metals overlap in these materials. Cuprates exhibit a large ‘super-exchange’ — the material trades electrons in copper atoms through a pathway that contains oxygen, rather than directly.

    “We think that may be one of the factors that governs superconductivity and causes the lower critical temperature of the nickelates,” she said. “We can look for ways of optimizing that characteristic.”

    Botana and colleagues Kwan-Woo Lee, Michael R. Norman, Victor Pardo, Warren E. Pickett described some of these differences in a review article for Frontiers in Physics in February 2022.

    Searching for Root Causes of Superconductivity

    Writing in Physical Review X in March 2022, Botana and collaborators from the Brookhaven National Laboratory and Argonne National Labs delved deeper into the role of oxygen states in the low-valence nickelate, La4Ni3O8. Using computational and experimental methods, they compared the material to a prototypical cuprate with a similar electron filling. The work was unique in that it directly measured the energy of the Nickel-Oxygen hybridized states.

    They found that despite requiring more energy to transfer charges, nickelates retained a sizable capacity for superexchange. They conclude that both the “Coulomb interactions” (the attraction or repulsion of particles or objects because of their electric charge) and charge-transfer processes need to be considered when interpreting the properties of nickelates.

    The quantum phenomena that Botana studies occur at the smallest scales known and can only be probed obliquely by physical experiment (as in the Physical Review X paper). Botana uses computational simulations to make predictions, help interpret experiments, and deduce the behavior and dynamics of materials like infinite-layer nickelate.

    Her research uses Density Functional Theory, or DFT — a means of computationally solving the Schrödinger equation that describes the wave function of a quantum-mechanical system — as well as a newer, more precise offshoot known as dynamical mean field theory that can treat electrons that are strongly correlated.

    To conduct her research, Botana uses the Stampede2 supercomputer of the Texas Advanced Computing Center (TACC) — the second fastest at any university in the U.S. — as well as machines at Arizona State University. Even on the fastest supercomputers in the world, studying quantum materials is no simple matter.

    “If I see a problem with too many atoms, I say, ‘I can’t study that,'” Botana said. “Twenty years ago, a few atoms might have looked like too much.” But more powerful supercomputers are allowing physicists to study larger, more complicated systems — like nickelates — and add tools, like dynamical mean field theory, that can better capture quantum behavior.

    Despite living in a Golden Age of Discovery, the field of condensed matter physics still doesn’t have the reputation it deserves, Botana says.

    “Your phone or computer would not be possible without research in condensed matter physics — from the screen, to the battery, to the little camera. It’s important for the public to understand that even if it’s fundamental research, and even if the researchers don’t know how it will be used later, this type of research in materials is critical.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The Texas Advanced Computing Center (TACC) at the University of Texas at Austin, United States, is an advanced computing research center that provides comprehensive advanced computing resources and support services to researchers in Texas and across the USA. The mission of TACC is to enable discoveries that advance science and society through the application of advanced computing technologies. Specializing in high performance computing, scientific visualization, data analysis & storage systems, software, research & development and portal interfaces, TACC deploys and operates advanced computational infrastructure to enable computational research activities of faculty, staff, and students of UT Austin. TACC also provides consulting, technical documentation, and training to support researchers who use these resources. TACC staff members conduct research and development in applications and algorithms, computing systems design/architecture, and programming tools and environments.

    Founded in 2001, TACC is one of the centers of computational excellence in the United States. Through the National Science Foundation (NSF) Extreme Science and Engineering Discovery Environment (XSEDE) project, TACC’s resources and services are made available to the national academic research community. TACC is located on UT’s J. J. Pickle Research Campus.

    TACC collaborators include researchers in other UT Austin departments and centers, at Texas universities in the High Performance Computing Across Texas Consortium, and at other U.S. universities and government laboratories.

    TACC Maverick HP NVIDIA supercomputer

    TACC Lonestar Cray XC40 supercomputer

    Dell Poweredge U Texas Austin Stampede Supercomputer. Texas Advanced Computer Center 9.6 PF

    TACC HPE Apollo 8000 Hikari supercomputer

    TACC Ranch long-term mass data storage system

    TACC DELL EMC Stampede2 supercomputer


    Stampede2 Arrives!

    TACC Frontera Dell EMC supercomputer fastest at any university

    University Texas at Austin

    U Texas Austin campus

    The University of Texas-Austin is a public research university in Austin, Texas and the flagship institution of the University of Texas System. Founded in 1883, the University of Texas was inducted into the Association of American Universities in 1929, becoming only the third university in the American South to be elected. The institution has the nation’s seventh-largest single-campus enrollment, with over 50,000 undergraduate and graduate students and over 24,000 faculty and staff.

    A Public Ivy, it is a major center for academic research. The university houses seven museums and seventeen libraries, including the LBJ Presidential Library and the Blanton Museum of Art, and operates various auxiliary research facilities, such as the J. J. Pickle Research Campus and the McDonald Observatory. As of November 2020, 13 Nobel Prize winners, four Pulitzer Prize winners, two Turing Award winners, two Fields medalists, two Wolf Prize winners, and two Abel prize winners have been affiliated with the school as alumni, faculty members or researchers. The university has also been affiliated with three Primetime Emmy Award winners, and has produced a total of 143 Olympic medalists.

    Student-athletes compete as the Texas Longhorns and are members of the Big 12 Conference. Its Longhorn Network is the only sports network featuring the college sports of a single university. The Longhorns have won four NCAA Division I National Football Championships, six NCAA Division I National Baseball Championships, thirteen NCAA Division I National Men’s Swimming and Diving Championships, and has claimed more titles in men’s and women’s sports than any other school in the Big 12 since the league was founded in 1996.

    Establishment

    The first mention of a public university in Texas can be traced to the 1827 constitution for the Mexican state of Coahuila y Tejas. Although Title 6, Article 217 of the Constitution promised to establish public education in the arts and sciences, no action was taken by the Mexican government. After Texas obtained its independence from Mexico in 1836, the Texas Congress adopted the Constitution of the Republic, which, under Section 5 of its General Provisions, stated “It shall be the duty of Congress, as soon as circumstances will permit, to provide, by law, a general system of education.”

    On April 18, 1838, “An Act to Establish the University of Texas” was referred to a special committee of the Texas Congress, but was not reported back for further action. On January 26, 1839, the Texas Congress agreed to set aside fifty leagues of land—approximately 288,000 acres (117,000 ha)—towards the establishment of a publicly funded university. In addition, 40 acres (16 ha) in the new capital of Austin were reserved and designated “College Hill”. (The term “Forty Acres” is colloquially used to refer to the University as a whole. The original 40 acres is the area from Guadalupe to Speedway and 21st Street to 24th Street.)

    In 1845, Texas was annexed into the United States. The state’s Constitution of 1845 failed to mention higher education. On February 11, 1858, the Seventh Texas Legislature approved O.B. 102, an act to establish the University of Texas, which set aside $100,000 in United States bonds toward construction of the state’s first publicly funded university (the $100,000 was an allocation from the $10 million the state received pursuant to the Compromise of 1850 and Texas’s relinquishing claims to lands outside its present boundaries). The legislature also designated land reserved for the encouragement of railroad construction toward the university’s endowment. On January 31, 1860, the state legislature, wanting to avoid raising taxes, passed an act authorizing the money set aside for the University of Texas to be used for frontier defense in west Texas to protect settlers from Indian attacks.

    Texas’s secession from the Union and the American Civil War delayed repayment of the borrowed monies. At the end of the Civil War in 1865, The University of Texas’s endowment was just over $16,000 in warrants and nothing substantive had been done to organize the university’s operations. This effort to establish a University was again mandated by Article 7, Section 10 of the Texas Constitution of 1876 which directed the legislature to “establish, organize and provide for the maintenance, support and direction of a university of the first class, to be located by a vote of the people of this State, and styled “The University of Texas”.

    Additionally, Article 7, Section 11 of the 1876 Constitution established the Permanent University Fund, a sovereign wealth fund managed by the Board of Regents of the University of Texas and dedicated to the maintenance of the university. Because some state legislators perceived an extravagance in the construction of academic buildings of other universities, Article 7, Section 14 of the Constitution expressly prohibited the legislature from using the state’s general revenue to fund construction of university buildings. Funds for constructing university buildings had to come from the university’s endowment or from private gifts to the university, but the university’s operating expenses could come from the state’s general revenues.

    The 1876 Constitution also revoked the endowment of the railroad lands of the Act of 1858, but dedicated 1,000,000 acres (400,000 ha) of land, along with other property appropriated for the university, to the Permanent University Fund. This was greatly to the detriment of the university as the lands the Constitution of 1876 granted the university represented less than 5% of the value of the lands granted to the university under the Act of 1858 (the lands close to the railroads were quite valuable, while the lands granted the university were in far west Texas, distant from sources of transportation and water). The more valuable lands reverted to the fund to support general education in the state (the Special School Fund).

    On April 10, 1883, the legislature supplemented the Permanent University Fund with another 1,000,000 acres (400,000 ha) of land in west Texas granted to the Texas and Pacific Railroad but returned to the state as seemingly too worthless to even survey. The legislature additionally appropriated $256,272.57 to repay the funds taken from the university in 1860 to pay for frontier defense and for transfers to the state’s General Fund in 1861 and 1862. The 1883 grant of land increased the land in the Permanent University Fund to almost 2.2 million acres. Under the Act of 1858, the university was entitled to just over 1,000 acres (400 ha) of land for every mile of railroad built in the state. Had the 1876 Constitution not revoked the original 1858 grant of land, by 1883, the university lands would have totaled 3.2 million acres, so the 1883 grant was to restore lands taken from the university by the 1876 Constitution, not an act of munificence.

    On March 30, 1881, the legislature set forth the university’s structure and organization and called for an election to establish its location. By popular election on September 6, 1881, Austin (with 30,913 votes) was chosen as the site. Galveston, having come in second in the election (with 20,741 votes), was designated the location of the medical department (Houston was third with 12,586 votes). On November 17, 1882, on the original “College Hill,” an official ceremony commemorated the laying of the cornerstone of the Old Main building. University President Ashbel Smith, presiding over the ceremony, prophetically proclaimed “Texas holds embedded in its earth rocks and minerals which now lie idle because unknown, resources of incalculable industrial utility, of wealth and power. Smite the earth, smite the rocks with the rod of knowledge and fountains of unstinted wealth will gush forth.” The University of Texas officially opened its doors on September 15, 1883.

    Expansion and growth

    In 1890, George Washington Brackenridge donated $18,000 for the construction of a three-story brick mess hall known as Brackenridge Hall (affectionately known as “B.Hall”), one of the university’s most storied buildings and one that played an important place in university life until its demolition in 1952.

    The old Victorian-Gothic Main Building served as the central point of the campus’s 40-acre (16 ha) site, and was used for nearly all purposes. But by the 1930s, discussions arose about the need for new library space, and the Main Building was razed in 1934 over the objections of many students and faculty. The modern-day tower and Main Building were constructed in its place.

    In 1910, George Washington Brackenridge again displayed his philanthropy, this time donating 500 acres (200 ha) on the Colorado River to the university. A vote by the regents to move the campus to the donated land was met with outrage, and the land has only been used for auxiliary purposes such as graduate student housing. Part of the tract was sold in the late-1990s for luxury housing, and there are controversial proposals to sell the remainder of the tract. The Brackenridge Field Laboratory was established on 82 acres (33 ha) of the land in 1967.

    In 1916, Gov. James E. Ferguson became involved in a serious quarrel with the University of Texas. The controversy grew out of the board of regents’ refusal to remove certain faculty members whom the governor found objectionable. When Ferguson found he could not have his way, he vetoed practically the entire appropriation for the university. Without sufficient funding, the university would have been forced to close its doors. In the middle of the controversy, Ferguson’s critics brought to light a number of irregularities on the part of the governor. Eventually, the Texas House of Representatives prepared 21 charges against Ferguson, and the Senate convicted him on 10 of them, including misapplication of public funds and receiving $156,000 from an unnamed source. The Texas Senate removed Ferguson as governor and declared him ineligible to hold office.

    In 1921, the legislature appropriated $1.35 million for the purchase of land next to the main campus. However, expansion was hampered by the restriction against using state revenues to fund construction of university buildings as set forth in Article 7, Section 14 of the Constitution. With the completion of Santa Rita No. 1 well and the discovery of oil on university-owned lands in 1923, the university added significantly to its Permanent University Fund. The additional income from Permanent University Fund investments allowed for bond issues in 1931 and 1947, which allowed the legislature to address funding for the university along with the Agricultural and Mechanical College (now known as Texas A&M University). With sufficient funds to finance construction on both campuses, on April 8, 1931, the Forty Second Legislature passed H.B. 368. which dedicated the Agricultural and Mechanical College a 1/3 interest in the Available University Fund, the annual income from Permanent University Fund investments.

    The University of Texas was inducted into The Association of American Universities in 1929. During World War II, the University of Texas was one of 131 colleges and universities nationally that took part in the V-12 Navy College Training Program which offered students a path to a Navy commission.

    In 1950, following Sweatt v. Painter, the University of Texas was the first major university in the South to accept an African-American student. John S. Chase went on to become the first licensed African-American architect in Texas.

    In the fall of 1956, the first black students entered the university’s undergraduate class. Black students were permitted to live in campus dorms, but were barred from campus cafeterias. The University of Texas integrated its facilities and desegregated its dorms in 1965. UT, which had had an open admissions policy, adopted standardized testing for admissions in the mid-1950s at least in part as a conscious strategy to minimize the number of Black undergraduates, given that they were no longer able to simply bar their entry after the Brown decision.

    Following growth in enrollment after World War II, the university unveiled an ambitious master plan in 1960 designed for “10 years of growth” that was intended to “boost the University of Texas into the ranks of the top state universities in the nation.” In 1965, the Texas Legislature granted the university Board of Regents to use eminent domain to purchase additional properties surrounding the original 40 acres (160,000 m^2). The university began buying parcels of land to the north, south, and east of the existing campus, particularly in the Blackland neighborhood to the east and the Brackenridge tract to the southeast, in hopes of using the land to relocate the university’s intramural fields, baseball field, tennis courts, and parking lots.

    On March 6, 1967, the Sixtieth Texas Legislature changed the university’s official name from “The University of Texas” to “The University of Texas at Austin” to reflect the growth of the University of Texas System.

    Recent history

    The first presidential library on a university campus was dedicated on May 22, 1971, with former President Johnson, Lady Bird Johnson and then-President Richard Nixon in attendance. Constructed on the eastern side of the main campus, the Lyndon Baines Johnson Library and Museum is one of 13 presidential libraries administered by the National Archives and Records Administration.

    A statue of Martin Luther King Jr. was unveiled on campus in 1999 and subsequently vandalized. By 2004, John Butler, a professor at the McCombs School of Business suggested moving it to Morehouse College, a historically black college, “a place where he is loved”.

    The University of Texas at Austin has experienced a wave of new construction recently with several significant buildings. On April 30, 2006, the school opened the Blanton Museum of Art. In August 2008, the AT&T Executive Education and Conference Center opened, with the hotel and conference center forming part of a new gateway to the university. Also in 2008, Darrell K Royal-Texas Memorial Stadium was expanded to a seating capacity of 100,119, making it the largest stadium (by capacity) in the state of Texas at the time.

    On January 19, 2011, the university announced the creation of a 24-hour television network in partnership with ESPN, dubbed the Longhorn Network. ESPN agreed to pay a $300 million guaranteed rights fee over 20 years to the university and to IMG College, the school’s multimedia rights partner. The network covers the university’s intercollegiate athletics, music, cultural arts, and academics programs. The channel first aired in September 2011.

     
  • richardmitnick 11:17 am on April 11, 2022 Permalink | Reply
    Tags: "In a Sea of Magic Angles ‘Twistons’ Keep Electrons Flowing Through Three Layers of Graphene", Adding a third layer of graphene improves the odds of finding superconductivity but the reason was unclear., , , Researchers at Columbia reveal new details about the physical structure of trilayer graphene that help explain why three layers are better than two for studying superconductivity., Superconductivity, , The discovery of superconductivity in two ever-so-slightly twisted layers of graphene made waves a few years ago in the quantum materials community., Trilayer graphene   

    From The Columbia Quantum Initiative: “In a Sea of Magic Angles ‘Twistons’ Keep Electrons Flowing Through Three Layers of Graphene” 

    1

    3

    From The Columbia Quantum Initiative

    at

    Columbia U bloc

    Columbia University (US)

    April 08, 2022
    Ellen Neff

    When it comes to superconductivity, three layers of graphene can be better than two. A new study from Columbia physicists reveals the atomic details that help explain why.

    1

    The discovery of superconductivity in two ever-so-slightly twisted layers of graphene made waves a few years ago in the quantum materials community. With just two atom-thin sheets of carbon, researchers had discovered a simple device to study the resistance-free flow of electricity, among other phenomena related to the movement of electrons through a material.

    But, the angle of twist between the two layers has to be just right—at the so-called “magic” angle of 1.1 degrees—for the phenomena to be observed. That’s because atoms in the layers want to resist the twist and “relax” back to a zero angle, explains Joshua Swann, a PhD student in the Dean Lab at Columbia. As magic angles vanish, so does superconductivity.

    Adding a third layer of graphene improves the odds of finding superconductivity but the reason was unclear. Writing in Science, researchers at Columbia reveal new details about the physical structure of trilayer graphene that help explain why three layers are better than two for studying superconductivity.

    Using a microscope capable of imaging down to the level of individual atoms, the team saw that groups of atoms in some areas were scrunching up into what Simon Turkel, a PhD student in the Pasupathy Lab, dubbed “twistons.” These twistons appeared in an orderly fashion, allowing the device as a whole to better maintain the magic angles necessary for superconductivity to occur.

    It’s an encouraging result said Swann, who built the device for the study. “I’ve made 20 or 30 bilayer graphene devices and seen maybe two or three that superconducted,” he said. “With three layers, you can explore properties that are hard to study in bilayer systems.”

    Those properties overlap with a class of complex materials called the cuprates, which superconduct at a relatively high temperature of -220 °F. A better understanding of the origins of superconductivity could help researchers develop wires that won’t lose energy as they conduct electricity or devices that won’t need to be kept at costly-to-maintain low temperatures.

    In the future, researchers hope to link what they see in their scans with measurements of quantum phenom in trilayer devices. “If we can control these twistons, which all depend on the angle mismatch between the top and bottom layers of the device, we can do systematic studies of their effects on superconductivity,” said Turkel. “It’s an exciting open question.”

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    In the first half of the 20th century, the first quantum revolution gave us a new way of thinking about the way the world works and brought us technologies such as lasers, MRI machines, and the transistors that underpin all aspects of modern life. Today, the second quantum revolution is underway, and it’s all about control.
    The coming generation of quantum technologies will be built on new physical principles and demand new materials, new methods of investigation, and new collaborations. At Columbia, we’re tackling these demands together and training the next generation of quantum scientists and entrepreneurs.
    Building on the collaborative culture long fostered at Columbia, the Columbia Quantum Initiative is combining interdisciplinary expertise in materials science, photonics, quantum theory, and more, all while taking advantage of our unique position in the global hub that is New York to develop novel quantum technologies that will open new frontiers into how we compute through complex problems, communicate with one another, and sense the world around us.

    Columbia U Campus
    Columbia University was founded in 1754 as King’s College by royal charter of King George II of England. It is the oldest institution of higher learning in the state of New York and the fifth oldest in the United States.

    University Mission Statement

    Columbia University is one of the world’s most important centers of research and at the same time a distinctive and distinguished learning environment for undergraduates and graduate students in many scholarly and professional fields. The University recognizes the importance of its location in New York City and seeks to link its research and teaching to the vast resources of a great metropolis. It seeks to attract a diverse and international faculty and student body, to support research and teaching on global issues, and to create academic relationships with many countries and regions. It expects all areas of the University to advance knowledge and learning at the highest level and to convey the products of its efforts to the world.

    Columbia University is a private Ivy League research university in New York City. Established in 1754 on the grounds of Trinity Church in Manhattan Columbia is the oldest institution of higher education in New York and the fifth-oldest institution of higher learning in the United States. It is one of nine colonial colleges founded prior to the Declaration of Independence, seven of which belong to the Ivy League. Columbia is ranked among the top universities in the world by major education publications.

    Columbia was established as King’s College by royal charter from King George II of Great Britain in reaction to the founding of Princeton College. It was renamed Columbia College in 1784 following the American Revolution, and in 1787 was placed under a private board of trustees headed by former students Alexander Hamilton and John Jay. In 1896, the campus was moved to its current location in Morningside Heights and renamed Columbia University.

    Columbia scientists and scholars have played an important role in scientific breakthroughs including brain-computer interface; the laser and maser; nuclear magnetic resonance; the first nuclear pile; the first nuclear fission reaction in the Americas; the first evidence for plate tectonics and continental drift; and much of the initial research and planning for the Manhattan Project during World War II. Columbia is organized into twenty schools, including four undergraduate schools and 15 graduate schools. The university’s research efforts include The Lamont–Doherty Earth Observatory, The Goddard Institute for Space Studies, and accelerator laboratories with major technology firms such as IBM. Columbia is a founding member of the The Association of American Universities and was the first school in the United States to grant the M.D. degree. With over 14 million volumes, Columbia University Library is the third largest private research library in the United States.

    The university’s endowment stands at $11.26 billion in 2020, among the largest of any academic institution. As of October 2020, Columbia’s alumni, faculty, and staff have included: five Founding Fathers of the United States—among them a co-author of the United States Constitution and a co-author of the Declaration of Independence; three U.S. presidents; 29 foreign heads of state; ten justices of the United States Supreme Court, one of whom currently serves; 96 Nobel laureates; five Fields Medalists; 122 National Academy of Sciences members; 53 living billionaires; eleven Olympic medalists; 33 Academy Award winners; and 125 Pulitzer Prize recipients.

     
  • richardmitnick 12:12 pm on February 20, 2022 Permalink | Reply
    Tags: "Summit study spins up new insights into correlated electron systems", An international team of researchers used Summit to model spin; charge and pair-density waves in cuprates-a type of copper alloy to explore the materials’ superconducting properties., , , , , Superconductivity,   

    From The DOE’s Oak Ridge National Laboratory (US) and The DOE’s Oak Ridge Leadership Computing Facility (US) : “Summit study spins up new insights into correlated electron systems” 

    From The DOE’s Oak Ridge National Laboratory (US)

    and

    The DOE’s Oak Ridge Leadership Computing Facility (US)

    February 18, 2022

    Scott Jones
    jonesg@ornl.gov
    865.241.6491

    1
    An international team of researchers used Summit to model spin, charge and pair-density waves in cuprates, a type of copper alloy, to explore the materials’ superconducting properties. The results revealed new insights into the relationships between these dynamics as superconductivity develops. Credit: Jason Smith/ORNL

    A study led by researchers at the U.S. Department of Energy’s Oak Ridge National Laboratory used the nation’s fastest supercomputer to close in on the answer to a central question of modern physics that could help conduct development of the next generation of energy technologies.

    “This is mostly about solving what’s now a decades-old problem,” said Thomas Maier, an ORNL physicist who led the study with researchers from the University of Tennessee and The Swiss Federal Institute of Technology ETH Zürich [Eidgenössische Technische Hochschule Zürich)](CH). “If we can answer the question of what’s the mechanism for superconductivity in certain correlated electron systems and understand the reasons for that behavior, then we can design materials to make the most of that behavior.”

    Findings appeared in the PNAS.

    The study used Summit, the Oak Ridge Leadership Computing Facility’s 200-petaflop IBM AC922 supercomputing system [below], to simulate interactions among a system of electrons within a solid. The simulations applied the Hubbard model [Nature Physics], the most straightforward model of a system of interacting electrons in various dimensions, to explore how a class of copper alloys known as cuprates act as superconductors that transmit electricity with no loss of energy.

    Cuprates can be used in power transmission and generation, high-speed magnetic levitation, or maglev, trains and medical applications, but generally display their full superconducting properties under extreme cold — typically hundreds of degrees below freezing. Explaining this superconductivity could crack the code to deliver superconductivity at room temperature and provide cheap, speedy and sustainable energy.

    The Hubbard model, developed nearly 60 years ago and named for British physicist John Hubbard, posits a system of electrons within a 2D lattice. Each electron has a spin — either up or down, similar to the positive and negative poles of a magnet — and no two electrons of the same spin can occupy the same site. The first term of the model describes kinetic energy. In this term, the electrons move or “hop” back and forth between adjacent sites in the lattice and diagonally between their next nearest neighbors. The second term describes interaction energy and the energy increase if two electrons of opposite spin try to occupy a single site.

    Hubbard didn’t design the model to explain electron behavior in superconductors like cuprates. Researchers have experimented with layers of copper and oxygen in search of a room-temperature superconductor and adjusted or “doped” the Hubbard model over the years to try to understand superconducting properties.

    The doped models remove electrons, leaving “holes” that encourage the remaining electrons to form pairs that easily conduct electricity. Under the right conditions, the holes fall in line to form stripes, believed by scientists to compete with superconductivity, and the electrons form a wave pattern, known as a charge and spin density wave.

    But those models so far fail to reliably explain or predict superconductivity in enough detail for practical use.

    “The approaches we have to solve this problem are not exact, and the model in theory would be infinite in size with many distinct phases, which requires extremely large, complex calculations,” Maier said. “Energy differences can be tiny — less than a millielectron volt. We can try to approximate all this in a finite-sized lattice, but that approach neglects too many aspects and we end up with a lattice too small to draw the kind of robust conclusions we’re looking for. We need a simple model that describes all the physics and consistently produces the same results.”

    Maier’s team received an allocation grant of 900,000 node hours on Summit via the DOE’s Innovative and Novel Computational Impact on Theory and Experiment, or INCITE, program to explore the model in depth. The results revealed new insights into the relationships between electron spin and charge stripes, including when stripes form as superconductivity develops.

    “These were some really heavy computations that couldn’t be done anywhere but on Summit,” Maier said. “We kind of took a chance, but it paid off because we finally had a machine that could support computations for a system large enough to see the stripes. This method allowed us to show that when the stripes show up in charge and spin, the superconducting correlations form a similar wave-like pattern known as a pair-density wave. The results could set a new standard for understanding this model.”

    The simulations don’t spell out the secret to raising the temperature for superconductivity. But the lessons learned point to targets for further study as researchers zero in on how superconducting occurs.

    “We know more each year than we did the last,” Maier said. “Now we need to explore other methods for solving the model and replicate the results. We’re closer now than ever before, and we want to get even closer.”

    Support for this research came from the DOE Office of Science’s INCITE program and Scientific Discovery through Advanced Computing program. The OLCF is an Office of Science user facility at ORNL.

    See the full article here .

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    The Oak Ridge Leadership Computing Facility (OLCF) was established at Oak Ridge National Laboratory in 2004 with the mission of accelerating scientific discovery and engineering progress by providing outstanding computing and data management resources to high-priority research and development projects.

    ORNL’s supercomputing program has grown from humble beginnings to deliver some of the most powerful systems in the world. On the way, it has helped researchers deliver practical breakthroughs and new scientific knowledge in climate, materials, nuclear science, and a wide range of other disciplines.

    The OLCF delivered on that original promise in 2008, when its Cray XT “Jaguar” system ran the first scientific applications to exceed 1,000 trillion calculations a second (1 petaflop). Since then, the OLCF has continued to expand the limits of computing power, unveiling Titan in 2013, which was capable of 27 petaflops.


    ORNL Cray XK7 Titan Supercomputer once No 1 in the world

    Titan was one of the first hybrid architecture systems—a combination of graphics processing units (GPUs), and the more conventional central processing units (CPUs) that have served as number crunchers in computers for decades. The parallel structure of GPUs makes them uniquely suited to process an enormous number of simple computations quickly, while CPUs are capable of tackling more sophisticated computational algorithms. The complimentary combination of CPUs and GPUs allow Titan to reach its peak performance.

    The OLCF gives the world’s most advanced computational researchers an opportunity to tackle problems that would be unthinkable on other systems. The facility welcomes investigators from universities, government agencies, and industry who are prepared to perform breakthrough research in climate, materials, alternative energy sources and energy storage, chemistry, nuclear physics, astrophysics, quantum mechanics, and the gamut of scientific inquiry. Because it is a unique resource, the OLCF focuses on the most ambitious research projects—projects that provide important new knowledge or enable important new technologies.


    Established in 1942, DOE’s Oak Ridge National Laboratory (US) is the largest science and energy national laboratory in the Department of Energy system (by size) and third largest by annual budget. It is located in the Roane County section of Oak Ridge, Tennessee. Its scientific programs focus on materials, neutron science, energy, high-performance computing, systems biology and national security, sometimes in partnership with the state of Tennessee, universities and other industries.

    ORNL has several of the world’s top supercomputers, including Summit, ranked by the TOP500 as Earth’s second-most powerful.

    ORNL OLCF IBM AC922 SUMMIT supercomputer, was No.1 on the TOP500..

    With a peak performance of 200,000 trillion calculations per second—or 200 petaflops, Summit will be eight times more powerful than ORNL’s previous top-ranked system, Titan. For certain scientific applications, Summit will also be capable of more than three billion billion mixed precision calculations per second, or 3.3 exaops. Summit will provide unprecedented computing power for research in energy, advanced materials and artificial intelligence (AI), among other domains, enabling scientific discoveries that were previously impractical or impossible.

    The lab is a leading neutron and nuclear power research facility that includes the Spallation Neutron Source and High Flux Isotope Reactor.

    ORNL Spallation Neutron Source annotated.

    It hosts the Center for Nanophase Materials Sciences, the BioEnergy Science Center, and the Consortium for Advanced Simulation of Light Water Nuclear Reactors.

    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time.

    Areas of research

    ORNL conducts research and development activities that span a wide range of scientific disciplines. Many research areas have a significant overlap with each other; researchers often work in two or more of the fields listed here. The laboratory’s major research areas are described briefly below.

    Chemical sciences – ORNL conducts both fundamental and applied research in a number of areas, including catalysis, surface science and interfacial chemistry; molecular transformations and fuel chemistry; heavy element chemistry and radioactive materials characterization; aqueous solution chemistry and geochemistry; mass spectrometry and laser spectroscopy; separations chemistry; materials chemistry including synthesis and characterization of polymers and other soft materials; chemical biosciences; and neutron science.
    Electron microscopy – ORNL’s electron microscopy program investigates key issues in condensed matter, materials, chemical and nanosciences.
    Nuclear medicine – The laboratory’s nuclear medicine research is focused on the development of improved reactor production and processing methods to provide medical radioisotopes, the development of new radionuclide generator systems, the design and evaluation of new radiopharmaceuticals for applications in nuclear medicine and oncology.
    Physics – Physics research at ORNL is focused primarily on studies of the fundamental properties of matter at the atomic, nuclear, and subnuclear levels and the development of experimental devices in support of these studies.
    Population – ORNL provides federal, state and international organizations with a gridded population database, called Landscan, for estimating ambient population. LandScan is a raster image, or grid, of population counts, which provides human population estimates every 30 x 30 arc seconds, which translates roughly to population estimates for 1 kilometer square windows or grid cells at the equator, with cell width decreasing at higher latitudes. Though many population datasets exist, LandScan is the best spatial population dataset, which also covers the globe. Updated annually (although data releases are generally one year behind the current year) offers continuous, updated values of population, based on the most recent information. Landscan data are accessible through GIS applications and a USAID public domain application called Population Explorer.

     
  • richardmitnick 1:05 pm on January 25, 2022 Permalink | Reply
    Tags: "The quantum squeeze", A new quantum sensor: the first practical superconducting transition-edge sensor., , , , In the 1960s researchers at the science lab of the Ford Motor Company developed the superconducting quantum interference device also known as a “SQUID.”, LIGO VIRGO KAGRA: Gravitational Wave Multimessenger Astrophysics Interferometry, , Quantum Squeezing: a way to circumvent quantum limitations that even quantum sensors have faced in the past., SQUIDs have played a key role in the development of ultrasensitive electric and magnetic measurement systems and are still in use., Superconductivity, , The Heisenberg Uncertainty Principle, The transition-edge sensor: It’s very much old-school quantum 1.0   

    From Symmetry: “The quantum squeeze” 

    Symmetry Mag

    From Symmetry

    01/25/22
    Evelyn Lamb

    1
    Illustration by Sandbox Studio, Chicago with Ana Kova.

    A technique from the newest generation of quantum sensors is helping scientists to use the limitations of the Heisenberg uncertainty principle to their advantage.

    In the 1960s researchers at the science lab of the Ford Motor Company developed the superconducting quantum interference device also known as a “SQUID.” It was the first usable sensor to take advantage of a quantum mechanical property—in this case, superconductivity.

    That made the SQUID one of the first generation of quantum sensors: devices that use a quantum system, quantum properties or quantum phenomena to make a physical measurement. Physicists took the idea and ran with it, coming up with new types of sensors they continue to use and improve today.

    SQUIDs have played a key role in the development of ultrasensitive electric and magnetic measurement systems and are still in use. For example, they amplify the detector signals for the Super Cryogenic Dark Matter Search. “As particle physicists, we’ve been using quantum sensing techniques for decades,” says SuperCDMS physicist Lauren Hsu of DOE’s Fermi National Accelerator Laboratory (US).

    Super Cryogenic Dark Matter Search from DOE’s SLAC National Accelerator Laboratory (US) at Stanford University (US) at SNOLAB (Vale Inco Mine, Sudbury, Canada).

    But SQUIDs are no longer the only quantum sensors around. One important recent development in quantum sensing is known as quantum squeezing—a way to circumvent quantum limitations that even quantum sensors have faced in the past.

    The first quantum sensors

    Ford’s SQUIDs, which needed to be cooled to a few degrees above absolute zero, used superconducting loops to measure minuscule magnetic fields.

    SQUIDs didn’t turn out to be of much use in an automobile. But not all Ford researchers were beholden to expectations that their creations would wind up in a car. “This shows you how different the world was back in the 1960s,” says Kent Irwin, a physicist at Stanford University (US) and DOE’s SLAC National Accelerator Laboratory (US). “These days Ford is not doing basic physics.”

    A few decades later, while in graduate school, Irwin built on the idea of the Ford Company’s SQUID to develop a new quantum sensor: the first practical superconducting transition-edge sensor.

    Irwin took advantage of the fact that superconducting material loses its superconductivity when it heats up, regaining its resistance at a precise temperature. By keeping a superconducting material as close as possible to this temperature limit, he could create a sensor that would undergo a significant change at the introduction of even a small amount of energy. Just a single photon hitting one of Irwin’s transition-edge sensors would cause it to shift to a different state.

    The transition-edge sensor is well-known and has been adopted widely in X-ray astronomy, dark matter detection, and measurements of the cosmic microwave background radiation. “It’s very much old-school quantum 1.0,” Irwin says.

    Quantum sensing for gravitational waves

    A new generation of quantum sensors goes beyond quantum 1.0. Some of today’s sensors make use of more than just superconductivity: They’ve managed to use the Heisenberg uncertainty principle—usually thought of as a limitation to how well physicists can make measurements—to their advantage.

    The Heisenberg uncertainty principle puts a cap on how accurately you can measure a pair of related properties. For example, the more you know about the position of a particle, the less you can know about its momentum.

    Quantum squeezing takes advantage of these relationships by purposefully tipping the balance: moving all the uncertainty of a measurement to one side or the other.

    Gravitational-wave detectors, such as LIGO in the US, and Virgo and GEO in Europe, have used quantum squeezing to great effect.
    _____________________________________________________________________________________
    LIGOVIRGOKAGRA

    Caltech /MIT Advanced aLigo.

    Caltech/MIT Advanced aLigo detector installation Livingston, LA, USA.

    Caltech/MIT Advanced aLigo Hanford, WA, USA installation.

    VIRGO Gravitational Wave interferometer, near Pisa, Italy.

    KAGRA Large-scale Cryogenic Gravitational Wave Telescope Project (JP).
    _____________________________________________________________________________________

    LIGO Virgo Kagra Masses in the Stellar Graveyard. Credit: Frank Elavsky and Aaron Geller at Northwestern University(US).

    In 2015, LIGO—the Laser-Interferometer Gravitational-wave Observatory—detected the first gravitational waves, undulations of spacetime first predicted by Albert Einstein. Once it got going, it was picking up new signs of gravitational-wave events every month.

    LIGO detects gravitational waves using an interferometer, an L-shaped device in which two beams of light are set up to bounce off identical mirrors and return [see above]. Under normal conditions, the beams will arrive at the same time and cancel one another out. No signal will hit the detector.

    But if a subtle outside force knocks them out of sync with one another, they won’t cancel each other out, and photons will hit the detector. If a gravitational wave passes through the two beams, it will hit one and then the other, interrupting their pattern.

    LIGO’s measurements are limited by the quantum properties of the photons that make up their beams of light. At the quantum level, photons are affected by fluctuations, virtual particles popping in and out of existence in the vacuum. Those fluctuations could cause a false signal in the detector. How could LIGO researchers tell the difference?

    “LIGO is using the most powerful lasers they can build, and the best mirrors they can build, and their back is against the wall,” Irwin says. “The only way to do better is to start beating quantum mechanics.”

    Scientists at LIGO and other gravitational-wave detectors looked to quantum squeezing to help them with their virtual photon problem.

    To generate squeezed light, researchers used a technology called an optical parametric oscillator, within which an input wave of laser light is converted to two output waves with smaller frequencies. This process entangles pairs of photons, and the resultant correlations of their properties serve to reduce uncertainty in one aspect of the arriving photons, allowing LIGO scientists to better measure another aspect, helping them sort the signal from the noise.

    Since April 2019, when LIGO began running with the quantum squeezers, the observatory has been able to detect new gravitational-wave signals—signs of collisions between massive objects such as black holes and neutron stars—more frequently, going from about one detection per month to about one per week.

    Quantum sensing for dark matter detection

    Quantum squeezing has also recently found an application in the search for Dark Matter.

    Dark Matter has never been observed directly, but clues in cosmology point to it making up approximately 85% of the matter in the universe. There are several different theories that describe what a Dark Matter particle could be.

    “The mass can be anywhere from a billionth the size of an electron up to a supermassive black hole,” Hsu says. “There are over 100 orders of magnitude that it can span.”

    The most promising small Dark Matter candidates are axions. In the presence of a strong magnetic field, axions occasionally convert into photons, which can then be detected by an experiment’s sensors.

    Like someone trying to find a radio station on a road trip in the middle of nowhere, they scan for a while at one frequency, to see if they detect a signal. If not, they turn the dial a little and try the next size up.

    It takes time to listen to each “station” once the detector is tuned to a particular possible axion signal; the more noise there is, the longer it takes to determine whether there might be a signal at all.

    The HAYSTAC experiment—for Haloscope at Yale Sensitive to Axion Cold Dark Matter—searches for axions by measuring two different components of electromagnetic field oscillations.

    Yale HAYSTAC axion dark matter experiment at Yale’s Wright Lab.

    Like LIGO, it is limited by the uncertainty principle; HAYSTAC researchers are unable to precisely measure both oscillations at once.

    But they didn’t need to. Like LIGO scientists, HAYSTAC scientists realized that if they could squeeze all the accuracy into just one side of the equation, it would improve the speed of their search. In early 2021, researchers announced that at HAYSTAC, they had also succeeded at using quantum squeezing to reduce noise levels in their experiment.

    Multiple groups have demonstrated promising new applications of superconducting circuit technology for axion detection.

    The “RF quantum upconverter” uses devices similar to Ford’s SQUIDs to evade the Heisenberg uncertainty principle in dark-matter searches at frequencies below HAYSTAC’s searches. Another uses a technology borrowed from quantum computing—qubits—as a sensor to evade Heisenberg’s limits at frequencies higher than HAYSTAC. Although neither technology has been used in dark matter searches yet, scientists believe that they could speed searches up by several orders of magnitude.

    At the current rate, it will still take axion experiments thousands of years to scan through every possible axion “station.” They may get lucky and find what they’re looking for early in the search, but it’s more likely that they’ll still need to find other ways to speed up their progress, perhaps with advances in quantum sensing, says Daniel Bowring, a Fermilab physicist who is involved in another axion search, the Axion Dark Matter Experiment.

    Inside the Axion Dark Matter eXperiment U Washington (US) Credit : Mark Stone U. of Washington. Axion Dark Matter Experiment.

    “It’s going to take a lot of people with really good imaginations,” Bowring says.

    See the full article here .


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    Symmetry is a joint Fermilab/SLAC publication.


     
  • richardmitnick 12:39 pm on January 24, 2022 Permalink | Reply
    Tags: "Physicists discover 'secret sauce' behind exotic properties of a new quantum material", , , Classical physics can be used to explain any number of phenomena that underlie our world-until things get exquisitely small., Enter quantum mechanics-the field that tries to explain the behavior of subatomic particles like electrons and quarks and resulting effects., In charge density waves the electrons arrange themselves in the shape of ripples-much like those in a sand dune., Kagome metal, Kagome metals can exhibit exotic properties such as unconventional superconductivity; nematicity and charge-density waves., MIT Materials Research Laboratory (US), , Superconductivity, The kagome metal family are composed of layers of atoms arranged in repeating units similar to a Star of David or sheriff’s badge., , The van Hove singularity involves the relationship between the electrons’ energy and velocity.   

    From The Massachusetts Institute of Technology (US): “Physicists discover ‘secret sauce’ behind exotic properties of a new quantum material” 

    MIT News

    From The Massachusetts Institute of Technology (US)

    January 21, 2022
    Elizabeth A. Thomson | MIT Materials Research Laboratory (US)

    1
    A visualization of the zero-energy electronic states — also known as a “Fermi surface” — from the kagome material studied by MIT’s Riccardo Comin and colleagues. Image courtesy of the Comin Laboratory.

    MIT physicists and colleagues have discovered the “secret sauce” behind some of the exotic properties of a new quantum material that has transfixed physicists due to those properties, which include superconductivity.

    Although theorists had predicted the reason for the unusual properties of the material, known as a kagome metal, this is the first time that the phenomenon behind those properties has been observed in the laboratory.

    “The hope is that our new understanding of the electronic structure of a kagome metal will help us build a rich platform for discovering other quantum materials,” says Riccardo Comin, the Class of 1947 Career Development Associate Professor of Physics at MIT, whose group led the study. That, in turn, could lead to a new class of superconductors, new approaches to quantum computing, and other quantum technologies.

    The work is reported in the Jan. 13 online issue of the journal Nature Physics.

    Classical physics can be used to explain any number of phenomena that underlie our world-until things get exquisitely small. Subatomic particles like electrons and quarks behave differently, in ways that are still not fully understood. Enter quantum mechanics, the field that tries to explain their behavior and resulting effects.

    The kagome metal at the heart of the current work is a new quantum material, or one that manifests the exotic properties of quantum mechanics at a macroscopic scale. In 2018 Comin and Joseph Checkelsky, MIT’s Mitsui Career Development Associate Professor of Physics, led the first study on the electronic structure of kagome metals, spurring interest into this family of materials. Members of the kagome metal family are composed of layers of atoms arranged in repeating units similar to a Star of David or sheriff’s badge. The pattern is also common in Japanese culture, particularly as a basket-weaving motif.

    “This new family of materials has attracted a lot of attention as a rich new playground for quantum matter that can exhibit exotic properties such as unconventional superconductivity, nematicity, and charge-density waves,” says Comin.

    Unusual properties

    Superconductivity and hints of charge density wave order in the new family of kagome metals studied by Comin and colleagues were discovered in the laboratory of Professor Stephen Wilson at The University of California -Santa Barbara (US), where single crystals were also synthesized (Wilson is a coauthor of the Nature Physics paper). The specific kagome material explored in the current work is made of only three elements (cesium, vanadium, and antimony) and has the chemical formula CsV3Sb5.

    The researchers focused on two of the exotic properties that a kagome metal shows when cooled below room temperatures. At those temperatures, electrons in the material begin to exhibit collective behavior. “They talk to each other, as opposed to moving independently,” says Comin.

    One of the resulting properties is superconductivity, which allows a material to conduct electricity extremely efficiently. In a regular metal, electrons behave much like people dancing individually in a room. In a kagome superconductor, when the material is cooled to 3 kelvins (about -454 degrees Fahrenheit) the electrons begin to move in pairs, like couples at a dance. “And all these pairs are moving in unison, as if they were part of a quantum choreography,” says Comin.

    At 100 K, the kagome material studied by Comin and collaborators exhibits yet another strange kind of behavior known as charge density waves. In this case, the electrons arrange themselves in the shape of ripples, much like those in a sand dune. “They’re not going anywhere; they’re stuck in place,” Comin says. A peak in the ripple represents a region that is rich in electrons. A valley is electron-poor. “Charge density waves are very different from a superconductor, but they’re still a state of matter where the electrons have to arrange in a collective, highly organized fashion. They form, again, a choreography, but they’re not dancing anymore. Now they form a static pattern.”

    Comin notes that kagome metals are of great interest to physicists in part because they can exhibit both superconductivity and charge density waves. “These two exotic phenomena are often in competition with one another, therefore it is unusual for a material to host both of them.”

    The secret sauce?

    But what is behind the emergence of these two properties? “What causes the electrons to start talking to each other, to start influencing each other? That is the key question,” says first author Mingu Kang, a graduate student in the MIT Department of Physics also affiliated with The MPG POSTECH Korea Research Initiative. That’s what the physicists report in Nature Physics. “By exploring the electronic structure of this new material, we discovered that the electrons exhibit an intriguing behavior known as an electronic singularity,” Kang says. This particular singularity is named for Léon van Hove, the Belgian physicist who first discovered it.

    The van Hove singularity involves the relationship between the electrons’ energy and velocity. Normally, the energy of a particle in motion is proportional to its velocity squared. “It’s a fundamental pillar of classical physics that [essentially] means the greater the velocity, the greater the energy,” says Comin. Imagine a Red Sox pitcher hitting you with a fast ball. Then imagine a kid trying to do the same. The pitcher’s ball would hurt a lot more than the kid’s, which has less energy.

    What the Comin team found is that in a kagome metal, this rule doesn’t hold anymore. Instead, electrons traveling with different velocities happen to all have the same energy. The result is that the pitcher’s fast ball would have the same physical effect as the kid’s. “It’s very counterintuitive,” Comin says. He noted that relating the energy to the velocity of electrons in a solid is challenging and requires special instruments at two international synchrotron research facilities: Beamline 4A1 of the Pohang Light Source and Beamline 7.0.2 (MAESTRO) of the Advanced Light Source at Lawrence Berkeley National Lab.

    3
    Pohang Light Source at The Pohang University of Science and Technology [성실; 창의; 진취](KR).

    Comments Professor Ronny Thomale of The Julius Maximilian University of Würzburg [Universität Würzburg](DE): “Theoretical physicists (including my group) have predicted the peculiar nature of van Hove singularities on the kagome lattice, a crystal structure made of corner-sharing triangles. Riccardo Comin has now provided the first experimental verification of these theoretical suggestions.” Thomale was not involved in the work.

    When many electrons exist at once with the same energy in a material, they are known to interact much more strongly. As a result of these interactions, the electrons can pair up and become superconducting, or otherwise form charge density waves. “The presence of a van Hove singularity in a material that has both makes perfect sense as the common source for these exotic phenomena” adds Kang. “Therefore, the presence of this singularity is the ‘secret sauce’ that enables the quantum behavior of kagome metals.”

    The team’s new understanding of the relationship between energy and velocities in the kagome material “is also important because it will enable us to establish new design principles for the development of new quantum materials,” Comin says. Further, “we now know how to find this singularity in other systems.”

    Direct feedback

    When physicists are analyzing data, most of the time that data must be processed before a clear trend is seen. The kagome system, however, “gave us direct feedback on what’s happening,” says Comin. “The best part of this study was being able to see the singularity right there in the raw data.”

    Additional authors of the Nature Physics paper are Shiang Fang of Rutgers University (US); Jeung-Kyu Kim, Jonggyu Yoo, and Jae-Hoon Park of Max Planck POSTECH/Korea Research Initiative and Pohang University of Science and Technology (Korea); Brenden Ortiz of the University of California-Santa Barbara (US); Jimin Kim of The Institute for Basic Science of Korea [기초과학연구원](KR); Giorgio Sangiovanni of the Universität Würzburg (Germany); Domenico Di Sante of The University of Bologna [Alma mater studiorum – Università di Bologna](IT) and The Flatiron Institute Center for Computational Astrophysics (US); Byeong-Gyu Park of Pohang Light Source (Korea); Sae Hee Ryu, Chris Jozwiak, Aaron Bostwick and Eli Rotenberg of DOE’s Lawrence Berkeley National Laboratory (US); and Efthimios Kaxiras of Harvard University (US).

    This work was funded by the Air Force Office of Scientific Research, the National Science Foundation, the National Research Foundation of Korea, a Samsung Scholarship, a Rutgers Center for Material Theory Distinguished Postdoctoral Fellowship, the California NanoSystems Institute, the European Union Horizon 2020 program, the German Research Foundation, and it used the resources of the Advanced Light Source, a Department of Energy Office of Science user facility.

    See the full article here .


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    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    The Massachusetts Institute of Technology (US) is a private land-grant research university in Cambridge, Massachusetts. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River. The institute also encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory (US), the MIT Bates Research and Engineering Center (US), and the Haystack Observatory (US), as well as affiliated laboratories such as the Broad Institute of MIT and Harvard(US) and Whitehead Institute (US).

    Massachusettes Institute of Technology-Haystack Observatory(US) Westford, Massachusetts, USA, Altitude 131 m (430 ft).

    Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology (US) adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.

    As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with The Massachusetts Institute of Technology (US) . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology (US) is a member of the Association of American Universities (AAU).

    Foundation and vision

    In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.

    Rogers, a professor from the University of Virginia (US), wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:

    “The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”

    The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.

    Early developments

    Two days after Massachusetts Institute of Technology (US) was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst (US)). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.

    Massachusetts Institute of Technology (US) was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.

    The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology (US) faculty and alumni rebuffed Harvard University (US) president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.

    In 1916, the Massachusetts Institute of Technology (US) administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.

    Curricular reforms

    In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology (US) catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities (US)in 1934.

    Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at Massachusetts Institute of Technology (US) that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.

    Massachusetts Institute of Technology (US)‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology (US)’s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, Massachusetts Institute of Technology (US) became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.

    These activities affected Massachusetts Institute of Technology (US) profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of Massachusetts Institute of Technology (US) between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, Massachusetts Institute of Technology (US) no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.

    In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and Massachusetts Institute of Technology (US)’s defense research. In this period Massachusetts Institute of Technology (US)’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. Massachusetts Institute of Technology (US) ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT (US) Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology (US) students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)

    In the 1980s, there was more controversy at Massachusetts Institute of Technology (US) over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, Massachusetts Institute of Technology (US)’s research for the military has included work on robots, drones and ‘battle suits’.

    Recent history

    Massachusetts Institute of Technology (US) has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology (US) classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.

    Massachusetts Institute of Technology (US) was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.

    In 2001, inspired by the open source and open access movements, Massachusetts Institute of Technology (US) launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, Massachusetts Institute of Technology (US) announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology (US) faculty adopted an open-access policy to make its scholarship publicly accessible online.

    Massachusetts Institute of Technology (US) has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology (US) community with thousands of police officers from the New England region and Canada. On November 25, 2013, Massachusetts Institute of Technology (US) announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of the Massachusetts Institute of Technology (US) community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.

    In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.

    The Caltech/MIT Advanced aLIGO (US) was designed and constructed by a team of scientists from California Institute of Technology (US), Massachusetts Institute of Technology (US), and industrial contractors, and funded by the National Science Foundation (US) .

    Caltech /MIT Advanced aLigo

    It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology (US) physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also an Massachusetts Institute of Technology (US) graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.

    The mission of Massachusetts Institute of Technology (US) is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of The Massachusetts Institute of Technology community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

     
  • richardmitnick 2:12 pm on January 11, 2022 Permalink | Reply
    Tags: "Physicists detect a hybrid particle held together by uniquely intense 'glue'", Antiferromagnets, , , , , , Superconductivity, The discovery could offer a route to smaller and faster electronic devices.,   

    From The Massachusetts Institute of Technology (US) : “Physicists detect a hybrid particle held together by uniquely intense ‘glue'” 

    MIT News

    From The Massachusetts Institute of Technology (US)

    January 10, 2022
    Jennifer Chu

    The discovery could offer a route to smaller and faster electronic devices.

    1
    MIT physicists have detected a hybrid particle in an unusual, two-dimensional magnetic material. The hybrid particle is a mashup of an electron and a phonon. Image: Christine Daniloff, MIT.

    In the particle world, sometimes two is better than one. Take, for instance, electron pairs. When two electrons are bound together, they can glide through a material without friction, giving the material special superconducting properties. Such paired electrons, or Cooper pairs, are a kind of hybrid particle — a composite of two particles that behaves as one, with properties that are greater than the sum of its parts.

    Now MIT physicists have detected another kind of hybrid particle in an unusual, two-dimensional magnetic material. They determined that the hybrid particle is a mashup of an electron and a phonon (a quasiparticle that is produced from a material’s vibrating atoms). When they measured the force between the electron and phonon, they found that the glue, or bond, was 10 times stronger than any other electron-phonon hybrid known to date.

    The particle’s exceptional bond suggests that its electron and phonon might be tuned in tandem; for instance, any change to the electron should affect the phonon, and vice versa. In principle, an electronic excitation, such as voltage or light, applied to the hybrid particle could stimulate the electron as it normally would, and also affect the phonon, which influences a material’s structural or magnetic properties. Such dual control could enable scientists to apply voltage or light to a material to tune not just its electrical properties but also its magnetism.

    The results are especially relevant, as the team identified the hybrid particle in nickel phosphorus trisulfide (NiPS3), a two-dimensional material that has attracted recent interest for its magnetic properties. If these properties could be manipulated, for instance through the newly detected hybrid particles, scientists believe the material could one day be useful as a new kind of magnetic semiconductor, which could be made into smaller, faster, and more energy-efficient electronics.

    “Imagine if we could stimulate an electron, and have magnetism respond,” says Nuh Gedik, professor of physics at MIT. “Then you could make devices very different from how they work today.”

    Gedik and his colleagues have published their results today in the journal Nature Communications. His co-authors include Emre Ergeçen, Batyr Ilyas, Dan Mao, Hoi Chun Po, Mehmet Burak Yilmaz, and Senthil Todadri at MIT, along with Junghyun Kim and Je-Geun Park of The Seoul National University [서울대학교](KR).

    Particle sheets

    The field of modern condensed matter physics is focused, in part, on the search for interactions in matter at the nanoscale. Such interactions, between a material’s atoms, electrons, and other subatomic particles, can lead to surprising outcomes, such as superconductivity and other exotic phenomena. Physicists look for these interactions by condensing chemicals onto surfaces to synthesize sheets of two-dimensional materials, which could be made as thin as one atomic layer.

    In 2018, a research group in Korea discovered some unexpected interactions in synthesized sheets of NiPS3, a two-dimensional material that becomes an antiferromagnet at very low temperatures of around 150 kelvins, or -123 degrees Celsius. The microstructure of an antiferromagnet resembles a honeycomb lattice of atoms whose spins are opposite to that of their neighbor. In contrast, a ferromagnetic material is made up of atoms with spins aligned in the same direction.

    In probing NiPS3, that group discovered that an exotic excitation became visible when the material is cooled below its antiferromagnetic transition, though the exact nature of the interactions responsible for this was unclear. Another group found signs of a hybrid particle, but its exact constituents and its relationship with this exotic excitation were also not clear.

    Gedik and his colleagues wondered if they might detect the hybrid particle, and tease out the two particles making up the whole, by catching their signature motions with a super-fast laser.

    Magnetically visible

    Normally, the motion of electrons and other subatomic particles are too fast to image, even with the world’s fastest camera. The challenge, Gedik says, is similar to taking a photo of a person running. The resulting image is blurry because the camera’s shutter, which lets in light to capture the image, is not fast enough, and the person is still running in the frame before the shutter can snap a clear picture.

    To get around this problem, the team used an ultrafast laser that emits light pulses lasting only 25 femtoseconds (one femtosecond is 1 millionth of 1 billionth of a second). They split the laser pulse into two separate pulses and aimed them at a sample of NiPS3. The two pulses were set with a slight delay from each other so that the first stimulated, or “kicked” the sample, while the second captured the sample’s response, with a time resolution of 25 femtoseconds. In this way, they were able to create ultrafast “movies” from which the interactions of different particles within the material could be deduced.

    In particular, they measured the precise amount of light reflected from the sample as a function of time between the two pulses. This reflection should change in a certain way if hybrid particles are present. This turned out to be the case when the sample was cooled below 150 kelvins, when the material becomes antiferromagnetic.

    “We found this hybrid particle was only visible below a certain temperature, when magnetism is turned on,” says Ergeçen.

    To identify the specific constituents of the particle, the team varied the color, or frequency, of the first laser and found that the hybrid particle was visible when the frequency of the reflected light was around a particular type of transition known to happen when an electron moves between two d-orbitals. They also looked at the spacing of the periodic pattern visible within the reflected light spectrum and found it matched the energy of a specific kind of phonon. This clarified that the hybrid particle consists of excitations of d-orbital electrons and this specific phonon.

    They did some further modeling based on their measurements and found the force binding the electron with the phonon is about 10 times stronger than what’s been estimated for other known electron-phonon hybrids.

    “One potential way of harnessing this hybrid particle is, it could allow you to couple to one of the components and indirectly tune the other,” Ilyas says. “That way, you could change the properties of a material, like the magnetic state of the system.”

    This research was supported, in part, by the U.S. Department of Energy and the Gordon and Betty Moore Foundation.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    The Massachusetts Institute of Technology (US) is a private land-grant research university in Cambridge, Massachusetts. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River. The institute also encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory (US), the MIT Bates Research and Engineering Center (US), and the Haystack Observatory (US), as well as affiliated laboratories such as the Broad Institute of MIT and Harvard(US) and Whitehead Institute (US).

    Massachusettes Institute of Technology-Haystack Observatory(US) Westford, Massachusetts, USA, Altitude 131 m (430 ft).

    Founded in 1861 in response to the increasing industrialization of the United States, Massachusetts Institute of Technology (US) adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. It has since played a key role in the development of many aspects of modern science, engineering, mathematics, and technology, and is widely known for its innovation and academic strength. It is frequently regarded as one of the most prestigious universities in the world.

    As of December 2020, 97 Nobel laureates, 26 Turing Award winners, and 8 Fields Medalists have been affiliated with MIT as alumni, faculty members, or researchers. In addition, 58 National Medal of Science recipients, 29 National Medals of Technology and Innovation recipients, 50 MacArthur Fellows, 80 Marshall Scholars, 3 Mitchell Scholars, 22 Schwarzman Scholars, 41 astronauts, and 16 Chief Scientists of the U.S. Air Force have been affiliated with The Massachusetts Institute of Technology (US) . The university also has a strong entrepreneurial culture and MIT alumni have founded or co-founded many notable companies. Massachusetts Institute of Technology (US) is a member of the Association of American Universities (AAU).

    Foundation and vision

    In 1859, a proposal was submitted to the Massachusetts General Court to use newly filled lands in Back Bay, Boston for a “Conservatory of Art and Science”, but the proposal failed. A charter for the incorporation of the Massachusetts Institute of Technology, proposed by William Barton Rogers, was signed by John Albion Andrew, the governor of Massachusetts, on April 10, 1861.

    Rogers, a professor from the University of Virginia (US), wanted to establish an institution to address rapid scientific and technological advances. He did not wish to found a professional school, but a combination with elements of both professional and liberal education, proposing that:

    “The true and only practicable object of a polytechnic school is, as I conceive, the teaching, not of the minute details and manipulations of the arts, which can be done only in the workshop, but the inculcation of those scientific principles which form the basis and explanation of them, and along with this, a full and methodical review of all their leading processes and operations in connection with physical laws.”

    The Rogers Plan reflected the German research university model, emphasizing an independent faculty engaged in research, as well as instruction oriented around seminars and laboratories.

    Early developments

    Two days after Massachusetts Institute of Technology (US) was chartered, the first battle of the Civil War broke out. After a long delay through the war years, MIT’s first classes were held in the Mercantile Building in Boston in 1865. The new institute was founded as part of the Morrill Land-Grant Colleges Act to fund institutions “to promote the liberal and practical education of the industrial classes” and was a land-grant school. In 1863 under the same act, the Commonwealth of Massachusetts founded the Massachusetts Agricultural College, which developed as the University of Massachusetts Amherst (US)). In 1866, the proceeds from land sales went toward new buildings in the Back Bay.

    Massachusetts Institute of Technology (US) was informally called “Boston Tech”. The institute adopted the European polytechnic university model and emphasized laboratory instruction from an early date. Despite chronic financial problems, the institute saw growth in the last two decades of the 19th century under President Francis Amasa Walker. Programs in electrical, chemical, marine, and sanitary engineering were introduced, new buildings were built, and the size of the student body increased to more than one thousand.

    The curriculum drifted to a vocational emphasis, with less focus on theoretical science. The fledgling school still suffered from chronic financial shortages which diverted the attention of the MIT leadership. During these “Boston Tech” years, Massachusetts Institute of Technology (US) faculty and alumni rebuffed Harvard University (US) president (and former MIT faculty) Charles W. Eliot’s repeated attempts to merge MIT with Harvard College’s Lawrence Scientific School. There would be at least six attempts to absorb MIT into Harvard. In its cramped Back Bay location, MIT could not afford to expand its overcrowded facilities, driving a desperate search for a new campus and funding. Eventually, the MIT Corporation approved a formal agreement to merge with Harvard, over the vehement objections of MIT faculty, students, and alumni. However, a 1917 decision by the Massachusetts Supreme Judicial Court effectively put an end to the merger scheme.

    In 1916, the Massachusetts Institute of Technology (US) administration and the MIT charter crossed the Charles River on the ceremonial barge Bucentaur built for the occasion, to signify MIT’s move to a spacious new campus largely consisting of filled land on a one-mile-long (1.6 km) tract along the Cambridge side of the Charles River. The neoclassical “New Technology” campus was designed by William W. Bosworth and had been funded largely by anonymous donations from a mysterious “Mr. Smith”, starting in 1912. In January 1920, the donor was revealed to be the industrialist George Eastman of Rochester, New York, who had invented methods of film production and processing, and founded Eastman Kodak. Between 1912 and 1920, Eastman donated $20 million ($236.6 million in 2015 dollars) in cash and Kodak stock to MIT.

    Curricular reforms

    In the 1930s, President Karl Taylor Compton and Vice-President (effectively Provost) Vannevar Bush emphasized the importance of pure sciences like physics and chemistry and reduced the vocational practice required in shops and drafting studios. The Compton reforms “renewed confidence in the ability of the Institute to develop leadership in science as well as in engineering”. Unlike Ivy League schools, Massachusetts Institute of Technology (US) catered more to middle-class families, and depended more on tuition than on endowments or grants for its funding. The school was elected to the Association of American Universities (US)in 1934.

    Still, as late as 1949, the Lewis Committee lamented in its report on the state of education at Massachusetts Institute of Technology (US) that “the Institute is widely conceived as basically a vocational school”, a “partly unjustified” perception the committee sought to change. The report comprehensively reviewed the undergraduate curriculum, recommended offering a broader education, and warned against letting engineering and government-sponsored research detract from the sciences and humanities. The School of Humanities, Arts, and Social Sciences and the MIT Sloan School of Management were formed in 1950 to compete with the powerful Schools of Science and Engineering. Previously marginalized faculties in the areas of economics, management, political science, and linguistics emerged into cohesive and assertive departments by attracting respected professors and launching competitive graduate programs. The School of Humanities, Arts, and Social Sciences continued to develop under the successive terms of the more humanistically oriented presidents Howard W. Johnson and Jerome Wiesner between 1966 and 1980.

    Massachusetts Institute of Technology (US)‘s involvement in military science surged during World War II. In 1941, Vannevar Bush was appointed head of the federal Office of Scientific Research and Development and directed funding to only a select group of universities, including MIT. Engineers and scientists from across the country gathered at Massachusetts Institute of Technology (US)’s Radiation Laboratory, established in 1940 to assist the British military in developing microwave radar. The work done there significantly affected both the war and subsequent research in the area. Other defense projects included gyroscope-based and other complex control systems for gunsight, bombsight, and inertial navigation under Charles Stark Draper’s Instrumentation Laboratory; the development of a digital computer for flight simulations under Project Whirlwind; and high-speed and high-altitude photography under Harold Edgerton. By the end of the war, Massachusetts Institute of Technology (US) became the nation’s largest wartime R&D contractor (attracting some criticism of Bush), employing nearly 4000 in the Radiation Laboratory alone and receiving in excess of $100 million ($1.2 billion in 2015 dollars) before 1946. Work on defense projects continued even after then. Post-war government-sponsored research at MIT included SAGE and guidance systems for ballistic missiles and Project Apollo.

    These activities affected Massachusetts Institute of Technology (US) profoundly. A 1949 report noted the lack of “any great slackening in the pace of life at the Institute” to match the return to peacetime, remembering the “academic tranquility of the prewar years”, though acknowledging the significant contributions of military research to the increased emphasis on graduate education and rapid growth of personnel and facilities. The faculty doubled and the graduate student body quintupled during the terms of Karl Taylor Compton, president of Massachusetts Institute of Technology (US) between 1930 and 1948; James Rhyne Killian, president from 1948 to 1957; and Julius Adams Stratton, chancellor from 1952 to 1957, whose institution-building strategies shaped the expanding university. By the 1950s, Massachusetts Institute of Technology (US) no longer simply benefited the industries with which it had worked for three decades, and it had developed closer working relationships with new patrons, philanthropic foundations and the federal government.

    In late 1960s and early 1970s, student and faculty activists protested against the Vietnam War and Massachusetts Institute of Technology (US)’s defense research. In this period Massachusetts Institute of Technology (US)’s various departments were researching helicopters, smart bombs and counterinsurgency techniques for the war in Vietnam as well as guidance systems for nuclear missiles. The Union of Concerned Scientists was founded on March 4, 1969 during a meeting of faculty members and students seeking to shift the emphasis on military research toward environmental and social problems. Massachusetts Institute of Technology (US) ultimately divested itself from the Instrumentation Laboratory and moved all classified research off-campus to the MIT (US) Lincoln Laboratory facility in 1973 in response to the protests. The student body, faculty, and administration remained comparatively unpolarized during what was a tumultuous time for many other universities. Johnson was seen to be highly successful in leading his institution to “greater strength and unity” after these times of turmoil. However six Massachusetts Institute of Technology (US) students were sentenced to prison terms at this time and some former student leaders, such as Michael Albert and George Katsiaficas, are still indignant about MIT’s role in military research and its suppression of these protests. (Richard Leacock’s film, November Actions, records some of these tumultuous events.)

    In the 1980s, there was more controversy at Massachusetts Institute of Technology (US) over its involvement in SDI (space weaponry) and CBW (chemical and biological warfare) research. More recently, Massachusetts Institute of Technology (US)’s research for the military has included work on robots, drones and ‘battle suits’.

    Recent history

    Massachusetts Institute of Technology (US) has kept pace with and helped to advance the digital age. In addition to developing the predecessors to modern computing and networking technologies, students, staff, and faculty members at Project MAC, the Artificial Intelligence Laboratory, and the Tech Model Railroad Club wrote some of the earliest interactive computer video games like Spacewar! and created much of modern hacker slang and culture. Several major computer-related organizations have originated at MIT since the 1980s: Richard Stallman’s GNU Project and the subsequent Free Software Foundation were founded in the mid-1980s at the AI Lab; the MIT Media Lab was founded in 1985 by Nicholas Negroponte and Jerome Wiesner to promote research into novel uses of computer technology; the World Wide Web Consortium standards organization was founded at the Laboratory for Computer Science in 1994 by Tim Berners-Lee; the MIT OpenCourseWare project has made course materials for over 2,000 Massachusetts Institute of Technology (US) classes available online free of charge since 2002; and the One Laptop per Child initiative to expand computer education and connectivity to children worldwide was launched in 2005.

    Massachusetts Institute of Technology (US) was named a sea-grant college in 1976 to support its programs in oceanography and marine sciences and was named a space-grant college in 1989 to support its aeronautics and astronautics programs. Despite diminishing government financial support over the past quarter century, MIT launched several successful development campaigns to significantly expand the campus: new dormitories and athletics buildings on west campus; the Tang Center for Management Education; several buildings in the northeast corner of campus supporting research into biology, brain and cognitive sciences, genomics, biotechnology, and cancer research; and a number of new “backlot” buildings on Vassar Street including the Stata Center. Construction on campus in the 2000s included expansions of the Media Lab, the Sloan School’s eastern campus, and graduate residences in the northwest. In 2006, President Hockfield launched the MIT Energy Research Council to investigate the interdisciplinary challenges posed by increasing global energy consumption.

    In 2001, inspired by the open source and open access movements, Massachusetts Institute of Technology (US) launched OpenCourseWare to make the lecture notes, problem sets, syllabi, exams, and lectures from the great majority of its courses available online for no charge, though without any formal accreditation for coursework completed. While the cost of supporting and hosting the project is high, OCW expanded in 2005 to include other universities as a part of the OpenCourseWare Consortium, which currently includes more than 250 academic institutions with content available in at least six languages. In 2011, Massachusetts Institute of Technology (US) announced it would offer formal certification (but not credits or degrees) to online participants completing coursework in its “MITx” program, for a modest fee. The “edX” online platform supporting MITx was initially developed in partnership with Harvard and its analogous “Harvardx” initiative. The courseware platform is open source, and other universities have already joined and added their own course content. In March 2009 the Massachusetts Institute of Technology (US) faculty adopted an open-access policy to make its scholarship publicly accessible online.

    Massachusetts Institute of Technology (US) has its own police force. Three days after the Boston Marathon bombing of April 2013, MIT Police patrol officer Sean Collier was fatally shot by the suspects Dzhokhar and Tamerlan Tsarnaev, setting off a violent manhunt that shut down the campus and much of the Boston metropolitan area for a day. One week later, Collier’s memorial service was attended by more than 10,000 people, in a ceremony hosted by the Massachusetts Institute of Technology (US) community with thousands of police officers from the New England region and Canada. On November 25, 2013, Massachusetts Institute of Technology (US) announced the creation of the Collier Medal, to be awarded annually to “an individual or group that embodies the character and qualities that Officer Collier exhibited as a member of the Massachusetts Institute of Technology (US) community and in all aspects of his life”. The announcement further stated that “Future recipients of the award will include those whose contributions exceed the boundaries of their profession, those who have contributed to building bridges across the community, and those who consistently and selflessly perform acts of kindness”.

    In September 2017, the school announced the creation of an artificial intelligence research lab called the MIT-IBM Watson AI Lab. IBM will spend $240 million over the next decade, and the lab will be staffed by MIT and IBM scientists. In October 2018 MIT announced that it would open a new Schwarzman College of Computing dedicated to the study of artificial intelligence, named after lead donor and The Blackstone Group CEO Stephen Schwarzman. The focus of the new college is to study not just AI, but interdisciplinary AI education, and how AI can be used in fields as diverse as history and biology. The cost of buildings and new faculty for the new college is expected to be $1 billion upon completion.

    The Caltech/MIT Advanced aLIGO (US) was designed and constructed by a team of scientists from California Institute of Technology (US), Massachusetts Institute of Technology (US), and industrial contractors, and funded by the National Science Foundation (US) .

    Caltech /MIT Advanced aLigo

    It was designed to open the field of gravitational-wave astronomy through the detection of gravitational waves predicted by general relativity. Gravitational waves were detected for the first time by the LIGO detector in 2015. For contributions to the LIGO detector and the observation of gravitational waves, two Caltech physicists, Kip Thorne and Barry Barish, and Massachusetts Institute of Technology (US) physicist Rainer Weiss won the Nobel Prize in physics in 2017. Weiss, who is also an Massachusetts Institute of Technology (US) graduate, designed the laser interferometric technique, which served as the essential blueprint for the LIGO.

    The mission of Massachusetts Institute of Technology (US) is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of The Massachusetts Institute of Technology community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

     
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