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  • richardmitnick 11:21 am on September 18, 2021 Permalink | Reply
    Tags: "First glimpse of hydrodynamic electron flow in 3D materials", , Condensed Matter Physics, Electrons flow through most materials more like a gas than a fluid meaning they don’t interact much with one another., , Hydrodynamic electron flow relies on strong interactions between electrons just as water and other fluids rely on strong interactions between their particles., , , , The researchers developed a new cryogenic scanning probe based on the nitrogen-vacancy defect in diamond., The researchers find evidence that the hydrodynamic character of the current strongly depends on the temperature., The researchers proposed that electrons in high density materials could interact with one another through the quantum vibrations of the atomic lattice known as phonons., This research provides a promising avenue for the search for hydrodynamic flow and prominent electron interactions in high-carrier-density materials.   

    From Harvard University John A Paulson School of Engineering and Applied Sciences (US) : “First glimpse of hydrodynamic electron flow in 3D materials” 

    From Harvard University John A Paulson School of Engineering and Applied Sciences (US)

    at

    Harvard University (US)

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    Credit: New Zealand Online News.

    September 16, 2021
    Leah Burrows

    Electrons flow through most materials more like a gas than a fluid meaning they don’t interact much with one another. It was long hypothesized that electrons could flow like a fluid, but only recent advances in materials and measurement techniques allowed these effects to be observed in 2D materials. In 2020, the labs of Amir Yacoby, Professor of Physics and of Applied Physics at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), Philip Kim, Professor of Physics and Professor Applied Physics at Harvard and Ronald Walsworth, formerly of the Department of Physics at Harvard, were among the first to image electrons [Nature] flowing in graphene like water flows through a pipe.

    The findings provided a new sandbox in which to explore electron interactions and offered a new way to control electrons — but only in two-dimensional materials. Electron hydrodynamics in three-dimensional materials remained much more elusive because of a fundamental behavior of electrons in conductors known as screening. When there is a high density of electrons in a material, as in conducting metals, electrons are less inclined to interact with one another.

    Recent research suggested that hydrodynamic electron flow in 3D conductors was possible, but exactly how it happened or how to observe it remained unknown. Until now.

    A team of researchers from Harvard and The Massachusetts Institute of Technology (US) developed a theory to explain how hydrodynamic electron flow could occur in 3D materials and observed it for the first time using a new imaging technique.

    The research is published in Nature Physics.

    “This research provides a promising avenue for the search for hydrodynamic flow and prominent electron interactions in high-carrier-density materials,” said Prineha Narang, Assistant Professor of Computational Materials Science at SEAS and a senior author of the study.

    Hydrodynamic electron flow relies on strong interactions between electrons just as water and other fluids rely on strong interactions between their particles. In order to flow efficiently, electrons in high density materials arrange themselves in such a way that limits interactions. It’s the same reason that group dances like the electric slide don’t involve a lot of interaction between dancers — with that many people, it’s easier for everyone to do their own moves.

    “To date, hydrodynamic effects have mostly been deduced from transport measurements, which effectively jumbles up the spatial signatures,” said Yacoby. “Our work has charted a different path in observing this dance and understanding hydrodynamics in systems beyond graphene with new quantum probes of electron correlations.”

    The researchers proposed that rather than direct interactions, electrons in high density materials could interact with one another through the quantum vibrations of the atomic lattice, known as phonons.

    “We can think of the phonon-mediated interactions between electrons by imagining two people jumping on a trampoline, who don’t propel each other directly but rather via the elastic force of the springs,” said Yaxian Wang, a postdoctoral scholar in the NarangLab at SEAS and co-author of the study.

    In order to observe this mechanism, the researchers developed a new cryogenic scanning probe based on the nitrogen-vacancy defect in diamond, which imaged the local magnetic field of a current flow in a material called layered semimetal tungsten ditelluride.

    “Our tiny quantum sensor is sensitive to small changes in the local magnetic field, allowing us to explore the magnetic structure in a material directly,” said Uri Vool, John Harvard distinguished science fellow and co-lead author of the study.

    Not only did the researchers find evidence of hydrodynamic flow within three-dimensional tungsten ditelluride but they also found that the hydrodynamic character of the current strongly depends on the temperature.

    “Hydrodynamic flow occurs in a narrow regime where temperature is not too high and not too low, and so the unique ability to scan across a wide temperature range was crucial to see the effect,” said Assaf Hamo, a postdoctoral scholar at the Yacoby lab and co-lead author of the study.

    “The ability to image and engineer these hydrodynamic flows in three-dimensional conductors as a function of temperature, opens up the possibility to achieve near dissipation-less electronics in nanoscale devices, as well as provides new insights into understanding electron-electron interactions,” said Georgios Varnavides, a Ph.D student in the NarangLab at SEAS and one of the lead authors of the study. ”The research also paves the way for exploring non-classical fluid behavior in hydrodynamic electron flow, such as steady-state vortices.”

    “This is an exciting and interdisciplinary field synthesizing concepts from condensed matter and materials science to computational hydrodynamics and statistical physics,” said Narang. In previous research, Varnavides and Narang classified different types of hydrodynamic behaviors which could arise in quantum materials where electrons flow collectively.

    This research was co-authored by Tony X. Zhou, Nitesh Kumar, Yuliya Dovzhenko, Ziwei Qiu, Christina A. C. Garcia, Andrew T. Pierce, Johannes Gooth, Polina Anikeeva, and Claudia Felser. It was supported in part by the US Department of Energy (DOE), Basic Energy Sciences Office, Division of Materials Sciences and Engineering, under award DE-SC0019300, Army Research Office grant no. W911NF-17-1-0023 and Army Research Office MURI (Ab-Initio Solid-State Quantum Materials) grant no. W911NF-18-1-0431 as well as the Gordon and Betty Moore Foundation through an EPiQS Initiative grant no. GBMF4531 and Moore Inventor Fellowship grant no.GBMF8048.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Through research and scholarship, the Harvard John A. Paulson School of Engineering and Applied Sciences (US) will create collaborative bridges across Harvard and educate the next generation of global leaders. By harnessing the power of engineering and applied sciences we will address the greatest challenges facing our society.

    Specifically, that means that SEAS will provide to all Harvard College students an introduction to and familiarity with engineering and technology as this is essential knowledge in the 21st century.

    Moreover, our concentrators will be immersed in the liberal arts environment and be able to understand the societal context for their problem solving, capable of working seamlessly with others, including those in the arts, the sciences, and the professional schools. They will focus on the fundamental engineering and applied science disciplines for the 21st century; as we will not teach legacy 20th century engineering disciplines.

    Instead, our curriculum will be rigorous but inviting to students, and be infused with active learning, interdisciplinary research, entrepreneurship and engineering design experiences. For our concentrators and graduate students, we will educate “T-shaped” individuals – with depth in one discipline but capable of working seamlessly with others, including arts, humanities, natural science and social science.

    To address current and future societal challenges, knowledge from fundamental science, art, and the humanities must all be linked through the application of engineering principles with the professions of law, medicine, public policy, design and business practice.

    In other words, solving important issues requires a multidisciplinary approach.

    With the combined strengths of SEAS, the Faculty of Arts and Sciences, and the professional schools, Harvard is ideally positioned to both broadly educate the next generation of leaders who understand the complexities of technology and society and to use its intellectual resources and innovative thinking to meet the challenges of the 21st century.

    Ultimately, we will provide to our graduates a rigorous quantitative liberal arts education that is an excellent launching point for any career and profession.

    Harvard University campus

    Harvard University (US) is the oldest institution of higher education in the United States, established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. It was named after the College’s first benefactor, the young minister John Harvard of Charlestown, who upon his death in 1638 left his library and half his estate to the institution. A statue of John Harvard stands today in front of University Hall in Harvard Yard, and is perhaps the University’s bestknown landmark.

    Harvard University (US) has 12 degree-granting Schools in addition to the Radcliffe Institute for Advanced Study. The University has grown from nine students with a single master to an enrollment of more than 20,000 degree candidates including undergraduate, graduate, and professional students. There are more than 360,000 living alumni in the U.S. and over 190 other countries.

    The Massachusetts colonial legislature, the General Court, authorized Harvard University (US)’s founding. In its early years, Harvard College primarily trained Congregational and Unitarian clergy, although it has never been formally affiliated with any denomination. Its curriculum and student body were gradually secularized during the 18th century, and by the 19th century, Harvard University (US) had emerged as the central cultural establishment among the Boston elite. Following the American Civil War, President Charles William Eliot’s long tenure (1869–1909) transformed the college and affiliated professional schools into a modern research university; Harvard became a founding member of the Association of American Universities in 1900. James B. Conant led the university through the Great Depression and World War II; he liberalized admissions after the war.

    The university is composed of ten academic faculties plus the Radcliffe Institute for Advanced Study. Arts and Sciences offers study in a wide range of academic disciplines for undergraduates and for graduates, while the other faculties offer only graduate degrees, mostly professional. Harvard has three main campuses: the 209-acre (85 ha) Cambridge campus centered on Harvard Yard; an adjoining campus immediately across the Charles River in the Allston neighborhood of Boston; and the medical campus in Boston’s Longwood Medical Area. Harvard University (US)’s endowment is valued at $41.9 billion, making it the largest of any academic institution. Endowment income helps enable the undergraduate college to admit students regardless of financial need and provide generous financial aid with no loans The Harvard Library is the world’s largest academic library system, comprising 79 individual libraries holding about 20.4 million items.

    Harvard University (US) has more alumni, faculty, and researchers who have won Nobel Prizes (161) and Fields Medals (18) than any other university in the world and more alumni who have been members of the U.S. Congress, MacArthur Fellows, Rhodes Scholars (375), and Marshall Scholars (255) than any other university in the United States. Its alumni also include eight U.S. presidents and 188 living billionaires, the most of any university. Fourteen Turing Award laureates have been Harvard affiliates. Students and alumni have also won 10 Academy Awards, 48 Pulitzer Prizes, and 108 Olympic medals (46 gold), and they have founded many notable companies.

    Colonial

    Harvard University (US) was established in 1636 by vote of the Great and General Court of the Massachusetts Bay Colony. In 1638, it acquired British North America’s first known printing press. In 1639, it was named Harvard College after deceased clergyman John Harvard, an alumnus of the University of Cambridge(UK) who had left the school £779 and his library of some 400 volumes. The charter creating the Harvard Corporation was granted in 1650.

    A 1643 publication gave the school’s purpose as “to advance learning and perpetuate it to posterity, dreading to leave an illiterate ministry to the churches when our present ministers shall lie in the dust.” It trained many Puritan ministers in its early years and offered a classic curriculum based on the English university model—many leaders in the colony had attended the University of Cambridge—but conformed to the tenets of Puritanism. Harvard University (US) has never affiliated with any particular denomination, though many of its earliest graduates went on to become clergymen in Congregational and Unitarian churches.

    Increase Mather served as president from 1681 to 1701. In 1708, John Leverett became the first president who was not also a clergyman, marking a turning of the college away from Puritanism and toward intellectual independence.

    19th century

    In the 19th century, Enlightenment ideas of reason and free will were widespread among Congregational ministers, putting those ministers and their congregations in tension with more traditionalist, Calvinist parties. When Hollis Professor of Divinity David Tappan died in 1803 and President Joseph Willard died a year later, a struggle broke out over their replacements. Henry Ware was elected to the Hollis chair in 1805, and the liberal Samuel Webber was appointed to the presidency two years later, signaling the shift from the dominance of traditional ideas at Harvard to the dominance of liberal, Arminian ideas.

    Charles William Eliot, president 1869–1909, eliminated the favored position of Christianity from the curriculum while opening it to student self-direction. Though Eliot was the crucial figure in the secularization of American higher education, he was motivated not by a desire to secularize education but by Transcendentalist Unitarian convictions influenced by William Ellery Channing and Ralph Waldo Emerson.

    20th century

    In the 20th century, Harvard University (US)’s reputation grew as a burgeoning endowment and prominent professors expanded the university’s scope. Rapid enrollment growth continued as new graduate schools were begun and the undergraduate college expanded. Radcliffe College, established in 1879 as the female counterpart of Harvard College, became one of the most prominent schools for women in the United States. Harvard University (US) became a founding member of the Association of American Universities in 1900.

    The student body in the early decades of the century was predominantly “old-stock, high-status Protestants, especially Episcopalians, Congregationalists, and Presbyterians.” A 1923 proposal by President A. Lawrence Lowell that Jews be limited to 15% of undergraduates was rejected, but Lowell did ban blacks from freshman dormitories.

    President James B. Conant reinvigorated creative scholarship to guarantee Harvard University (US)’s preeminence among research institutions. He saw higher education as a vehicle of opportunity for the talented rather than an entitlement for the wealthy, so Conant devised programs to identify, recruit, and support talented youth. In 1943, he asked the faculty to make a definitive statement about what general education ought to be, at the secondary as well as at the college level. The resulting Report, published in 1945, was one of the most influential manifestos in 20th century American education.

    Between 1945 and 1960, admissions were opened up to bring in a more diverse group of students. No longer drawing mostly from select New England prep schools, the undergraduate college became accessible to striving middle class students from public schools; many more Jews and Catholics were admitted, but few blacks, Hispanics, or Asians. Throughout the rest of the 20th century, Harvard became more diverse.

    Harvard University (US)’s graduate schools began admitting women in small numbers in the late 19th century. During World War II, students at Radcliffe College (which since 1879 had been paying Harvard University (US) professors to repeat their lectures for women) began attending Harvard University (US) classes alongside men. Women were first admitted to the medical school in 1945. Since 1971, Harvard University (US) has controlled essentially all aspects of undergraduate admission, instruction, and housing for Radcliffe women. In 1999, Radcliffe was formally merged into Harvard University (US).

    21st century

    Drew Gilpin Faust, previously the dean of the Radcliffe Institute for Advanced Study, became Harvard University (US)’s first woman president on July 1, 2007. She was succeeded by Lawrence Bacow on July 1, 2018.

     
  • richardmitnick 11:54 am on July 30, 2021 Permalink | Reply
    Tags: "Eternal Change for No Energy-A Time Crystal Finally Made Real", A time crystal is an object whose parts move in a regular repeating cycle sustaining this constant change without burning any energy., , Condensed Matter Physics, Evading the second law of thermodynamics., Floquet time crystal, Google Sycamore quantum computer, , , , Researchers at Google in collaboration with physicists at Stanford and Princeton and other universities say that they have used Google’s quantum computer to demonstrate a genuine “time crystal” , Researchers have raced to create a time crystal over the past five years but previous demos successful on their own terms have failed to satisfy the criteria needed to establish its existence., The time crystal is a new category of phases of matter expanding the definition of what a phase is., Time crystals are also the first objects to spontaneously break “time-translation symmetry.”   

    From Quanta Magazine (US) : “Eternal Change for No Energy-A Time Crystal Finally Made Real” 

    From Quanta Magazine (US)

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    Maylee for Quanta Magazine
    .


    A time crystal flips back and forth between two states without burning energy.
    Maylee for Quanta Magazine.

    In a preprint posted online Thursday night, researchers at Google in collaboration with physicists at Stanford University (US), Princeton University (US) and other universities say that they have used Google’s quantum computer to demonstrate a genuine “time crystal” for the first time.

    A novel phase of matter that physicists have strived to realize for many years, a time crystal is an object whose parts move in a regular repeating cycle sustaining this constant change without burning any energy.

    “The consequence is amazing: You evade the second law of thermodynamics,” said co-author Roderich Moessner, director of the MPG Institute for the Physics of Complex Systems [MPG Institut für Physik komplexer Systeme] (DE) in Dresden, Germany. That’s the law that says disorder always increases.

    Time crystals are also the first objects to spontaneously break “time-translation symmetry,” the usual rule that a stable object will remain the same throughout time. A time crystal is both stable and ever-changing, with special moments that come at periodic intervals in time.

    The time crystal is a new category of phases of matter expanding the definition of what a phase is. All other known phases, like water or ice, are in thermal equilibrium: Their constituent atoms have settled into the state with the lowest energy permitted by the ambient temperature, and their properties don’t change with time. The time crystal is the first “out-of-equilibrium” phase: It has order and perfect stability despite being in an excited and evolving state.

    “This is just this completely new and exciting space that we’re working in now,” said Vedika Khemani, a condensed matter physicist now at Stanford who co-discovered the novel phase while she was a graduate student and co-authored the new paper.

    Khemani, Moessner, Shivaji Sondhi of Princeton and Achilleas Lazarides of Loughborough University (UK) in the United Kingdom discovered the possibility of the phase and described its key properties in 2015; a rival group of physicists led by Chetan Nayak of Microsoft Station Q and the University of California-Santa Barbara (US) identified it as a time crystal soon after.

    Researchers have raced to create a time crystal over the past five years, but previous demos, though successful on their own terms, have failed to satisfy all the criteria needed to establish the time crystal’s existence. “There are good reasons to think that none of those experiments completely succeeded, and a quantum computer like [Google’s] would be particularly well placed to do much better than those earlier experiments,” said John Chalker, a condensed matter physicist at the University of Oxford (UK) who wasn’t involved in the new work.

    Google’s quantum computing team made headlines in 2019 when they performed the first-ever computation that ordinary computers weren’t thought to be able to do in a practical amount of time. Yet that task was contrived to show a speedup and was of no inherent interest. The new time crystal demo marks one of the first times a quantum computer has found gainful employment.

    “It’s a fantastic use of [Google’s] processor,” Nayak said.

    With today’s preprint, which has been submitted for publication, and other recent results, researchers have fulfilled the original hope for quantum computers. In his 1982 paper proposing the devices, the physicist Richard Feynman argued that they could be used to simulate the particles of any imaginable quantum system.

    A time crystal exemplifies that vision. It’s a quantum object that nature itself probably never creates, given its complex combination of delicate ingredients. Imaginations conjured the recipe, stirred by nature’s most baffling laws.

    An Impossible Idea, Resurrected

    The original notion of a time crystal had a fatal flaw.

    The Nobel Prize­-winning physicist Frank Wilczek conceived the idea in 2012, while teaching a class about ordinary (spatial) crystals. “If you think about crystals in space, it’s very natural also to think about the classification of crystalline behavior in time,” he told this magazine not long after.

    Consider a diamond, a crystalline phase of a clump of carbon atoms. The clump is governed by the same equations everywhere in space, yet it takes a form that has periodic spatial variations, with atoms positioned at lattice points. Physicists say that it “spontaneously breaks space-translation symmetry.” Only minimum-energy equilibrium states spontaneously break spatial symmetries in this way.

    Wilczek envisioned a multi-part object in equilibrium, much like a diamond. But this object breaks time-translation symmetry: It undergoes periodic motion, returning to its initial configuration at regular intervals.

    Wilczek’s proposed time crystal was profoundly different from, say, a wall clock — an object that also undergoes periodic motion. Clock hands burn energy and stop when the battery runs out. A Wilczekian time crystal requires no input and continues indefinitely, since the system is in its ultra-stable equilibrium state.

    If it sounds implausible, it is: After much thrill and controversy, a 2014 proof showed that Wilczek’s prescription fails, like all other perpetual-motion machines conceived throughout history.

    That year, researchers at Princeton were thinking about something else. Khemani and her doctoral adviser, Sondhi, were studying many-body localization, an extension of Anderson localization, the Nobel Prize-winning 1958 discovery that an electron can get stuck in place, as if in a crevice in a rugged landscape.

    An electron is best pictured as a wave, whose height in different places gives the probability of detecting the particle there. The wave naturally spreads out over time. But Philip Anderson discovered that randomness — such as the presence of random defects in a crystal lattice — can cause the electron’s wave to break up, destructively interfere with itself, and cancel out everywhere except in a small region. The particle localizes.

    People thought for decades that interactions between multiple particles would destroy the interference effect. But in 2005, three physicists at Princeton and Columbia University (US) showed that a one-dimensional chain of quantum particles can experience many-body localization; that is, they all get stuck in a fixed state. This phenomenon would become the first ingredient of the time crystal.

    Imagine a row of particles, each with a magnetic orientation (or “spin”) that points up, down, or some probability of both directions. Imagine that the first four spins initially point up, down, down and up. The spins will quantum mechanically fluctuate and quickly align, if they can. But random interference between them can cause the row of particles to get stuck in their particular configuration, unable to rearrange or settle into thermal equilibrium. They’ll point up, down, down and up indefinitely.

    Sondhi and a collaborator had discovered that many-body localized systems can exhibit a special kind of order, which would become the second key ingredient of a time crystal: If you flip all the spins in the system (yielding down, up, up and down in our example), you get another stable, many-body localized state.

    3
    Samuel Velasco/Quanta Magazine.

    In the fall of 2014, Khemani joined Sondhi on sabbatical at the Max Planck Institute in Dresden. There, Moessner and Lazarides specialized in so-called Floquet systems: periodically driven systems, such as a crystal that’s being stimulated with a laser of a certain frequency. The laser’s intensity, and thus the strength of its effect on the system, periodically varies.

    Moessner, Lazarides, Sondhi and Khemani studied what happens when a many-body localized system is periodically driven in this way. They found in calculations and simulations that when you tickle a localized chain of spins with a laser in a particular way, they’ll flip back and forth, moving between two different many-body localized states in a repeating cycle forever without absorbing any net energy from the laser.

    They called their discovery a pi spin-glass phase (where the angle pi signifies a 180-degree flip). The group reported the concept of this new phase of matter — the first many-body, out-of-equilibrium phase ever identified — in a 2015 preprint, but the words “time crystal” didn’t appear anywhere in it. The authors added the term in an updated version, published in Physical Review Letters in June 2016, thanking a reviewer in the acknowledgments for making the connection between their pi spin-glass phase and time crystals.

    Something else happened between the preprint’s appearance and its publication: Nayak, who is a former graduate student of Wilczek’s, and collaborators Dominic Else and Bela Bauer put out a preprint in March 2016 proposing the existence of objects called Floquet time crystals. They pointed to Khemani and company’s pi spin-glass phase as an example.

    A Floquet time crystal exhibits the kind of behavior envisioned by Wilczek, but only while being periodically driven by an external energy source. This kind of time crystal circumvents the failure of Wilczek’s original idea by never professing to be in thermal equilibrium. Because it’s a many-body localized system, its spins or other parts are unable to settle into equilibrium; they’re stuck where they are. But the system doesn’t heat up either, despite being pumped by a laser or other driver. Instead, it cycles back and forth indefinitely between localized states.

    Already, the laser will have broken the symmetry between all moments in time for the row of spins, imposing instead “discrete time-translation symmetry” — that is, identical conditions only after each periodic cycle of the laser. But then, through its back-and-forth flips, the row of spins further breaks the discrete time-translation symmetry imposed by the laser, since its own periodic cycles are multiples of the laser’s.

    Khemani and co-authors had characterized this phase in detail, but Nayak’s group couched it in the language of time, symmetry and spontaneous symmetry-breaking — all fundamental concepts in physics. As well as offering sexier terminology, they provided new facets of understanding, and they slightly generalized the notion of a Floquet time crystal beyond the pi spin-glass phase (noting that a certain symmetry it has isn’t needed). Their paper was published in Physical Review Letters in August 2016, two months after Khemani and company published the theoretical discovery of the first example of the phase.

    Both groups claim to have discovered the idea. Since then, the rival researchers and others have raced to create a time crystal in reality.

    The Perfect Platform

    Nayak’s crew teamed up with Chris Monroe at the University of Maryland (US), who uses electromagnetic fields to trap and control ions. Last month, the group reported in Science that they’d turned the trapped ions into an approximate, or “prethermal,” time crystal. Its cyclical variations (in this case, ions jumping between two states) are practically indistinguishable from those of a genuine time crystal. But unlike a diamond, this prethermal time crystal is not forever; if the experiment ran for long enough, the system would gradually equilibrate and the cyclical behavior would break down.

    Khemani, Sondhi, Moessner and collaborators hitched their wagon elsewhere. In 2019, Google announced that its Sycamore quantum computer had completed a task in 200 seconds that would take a conventional computer 10,000 years. (Other researchers would later describe a way to greatly speed up the ordinary computer’s calculation.) In reading the announcement paper, Moessner said, he and his colleagues realized that “the Sycamore processor contains as its fundamental building blocks exactly the things we need to realize the Floquet time crystal.”

    Serendipitously, Sycamore’s developers were also looking for something to do with their machine, which is too error-prone to run the cryptography and search algorithms designed for full-fledged quantum computers. When Khemani and colleagues reached out to Kostya Kechedzhi, a theorist at Google, he and his team quickly agreed to collaborate on the time crystal project. “My work, not only with discrete time crystals but other projects, is to try and use our processor as a scientific tool to study new physics or chemistry,” Kechedzhi said.


    Video: Quantum computers aren’t the next generation of supercomputers — they’re something else entirely. Before we can even begin to talk about their potential applications, we need to understand the fundamental physics that drives the theory of quantum computing. Credit:Emily Buder/Quanta Magazine; Chris FitzGerald and DVDP for Quanta Magazine.

    Quantum computers consist of “qubits” — essentially controllable quantum particles, each of which can maintain two possible states, labeled 0 and 1, at the same time. When qubits interact, they can collectively juggle an exponential number of simultaneous possibilities, enabling computing advantages.

    Google’s qubits consist of superconducting aluminum strips. Each has two possible energy states, which can be programmed to represent spins pointing up or down. For the demo, Kechedzhi and collaborators used a chip with 20 qubits to serve as the time crystal.

    Perhaps the main advantage of the machine over its competitors is its ability to tune the strengths of interactions between its qubits. This tunability is key to why the system could become a time crystal: The programmers could randomize the qubits’ interaction strengths, and this randomness created destructive interference between them that allowed the row of spins to achieve many-body localization. The qubits could lock into a set pattern of orientations rather than aligning.

    The researchers gave the spins arbitrary initial configurations, such as: up, down, down, up, and so on. Pumping the system with microwaves flipped up-pointing spins to down and vice versa. By running tens of thousands of demos for each initial configuration and measuring the states of the qubits after different amounts of time in each run, the researchers could observe that the system of spins was flipping back and forth between two many-body localized states.

    The hallmark of a phase is extreme stability. Ice stays as ice even if the temperature fluctuates. Indeed, the researchers found that microwave pulses only had to flip spins somewhere in the ballpark of 180 degrees, but not exactly that much, for the spins to return to their exact initial orientation after two pulses, like little boats righting themselves. Furthermore, the spins never absorbed or dissipated net energy from the microwave laser, leaving the disorder of the system unchanged.

    It’s unclear whether a Floquet time crystal might have practical use. But its stability seems promising to Moessner. “Something that’s as stable as this is unusual, and special things become useful,” he said.

    Or the state might be merely conceptually useful. It’s the first and simplest example of an out-of-equilibrium phase, but the researchers suspect that more such phases are physically possible.

    Nayak argues that time crystals illuminate something profound about the nature of time. Normally in physics, he said, “however much you try to treat [time] as being just another dimension, it is always kind of an outlier.” Einstein made the best attempt at unification, weaving 3D space together with time into a four-dimensional fabric: space-time. But even in his theory, unidirectional time is unique. With time crystals, Nayak said, “this is the first case that I know of where all of a sudden time is just one of the gang.”

    Chalker argues, though, that time remains an outlier. Wilczek’s time crystal would have been a true unification of time and space, he said. Spatial crystals are in equilibrium, and relatedly, they break continuous space-translation symmetry. The discovery that, in the case of time, only discrete time-translation symmetry may be broken by time crystals puts a new angle on the distinction between time and space.

    These discussions will continue, driven by the possibility of exploration on quantum computers. Condensed matter physicists used to concern themselves with the phases of the natural world. “The focus moved from studying what nature gives us,” Chalker said, to dreaming up exotic forms of matter that quantum mechanics allows.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Formerly known as Simons Science News, Quanta Magazine (US) 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 11:24 am on July 15, 2021 Permalink | Reply
    Tags: "New mechanism of superconductivity discovered in graphene", , , Condensed Matter Physics, , , Placing a 2D Bose-Einstein condensate in the vicinity of a graphene layer confers superconductivity to the material.   

    From Institute for Basic Science [ 기초과학연구원](KR): “New mechanism of superconductivity discovered in graphene” 

    From Institute for Basic Science [ 기초과학연구원](KR)

    2021-04-14 [Just now in social media.]
    Park Jong Woo

    Placing a 2D Bose-Einstein condensate in the vicinity of a graphene layer confers superconductivity to the material.

    Superconductivity is a physical phenomenon where the electrical resistance of a material drops to zero under a certain critical temperature. Bardeen-Cooper-Schrieffer (BCS) theory is a well-established explanation that describes superconductivity in most materials. It states that Cooper pairs of electrons are formed in the lattice under sufficiently low temperature and that BCS superconductivity arises from their condensation. While graphene itself is an excellent conductor of electricity, it does not exhibit BCS superconductivity due to the suppression of electron-phonon interactions. This is also the reason that most ‘good’ conductors such as gold and copper are ‘bad’ superconductors.

    Researchers at the Center for Theoretical Physics of Complex Systems (PCS), within the Institute for Basic Science (IBS, South Korea) have reported on a novel alternative mechanism to achieve superconductivity in graphene. They achieved this feat by proposing a hybrid system consisting of graphene and 2D Bose-Einstein condensate (BEC). This research is published in the journal 2D Materials.

    1
    Figure 1. A hybrid system consisting of an electron gas in graphene (top layer) separated from a two-dimensional Bose-Einstein condensate, represented by indirect excitons (blue and red layers). The electrons in the graphene and the excitons are coupled by the Coulomb force.

    Along with superconductivity, BEC is another phenomenon that arises at low temperatures. It is the fifth state of matter first predicted by Einstein in 1924. The formation of BEC occurs when low-energy atoms clump together and enter the same energy state, and it is an area that is widely studied in condensed matter physics. A hybrid Bose-Fermi system essentially represents a layer of electrons interacting with a layer of bosons, such as indirect excitons, exciton-polaritons, etc. The interaction between Bose and Fermi particles leads to various novel fascinating phenomena, which piques interests from both the fundamental and application-oriented perspectives.

    In this work, the researchers report a new mechanism of superconductivity in graphene, which arises due to interactions between electrons and “bogolons”, rather than phonons as in typical BCS systems. Bogolons, or Bogoliubov quasiparticles, are excitation within BEC which has some characteristics of a particle. In certain ranges of parameters, this mechanism permits the critical temperature for superconductivity up to 70 Kelvin within graphene. The researchers also developed a new microscopic BCS theory which focuses specifically on the novel hybrid graphene-based system. Their proposed model also predicts that superconducting properties can be enhanced with temperature, resulting in the non-monotonous temperature dependence of the superconducting gap.

    Furthermore, the research showed that the Dirac dispersion of graphene is preserved in this bogolon-mediated scheme. This indicates that this superconducting mechanism involves electrons with relativistic dispersion — a phenomenon that is not so well-explored in condensed matter physics.

    “This work sheds light on an alternative way to achieve high-temperature superconductivity. Meanwhile, by controlling the properties of a condensate, we can tune the superconductivity of graphene. This suggests another channel to control the superconductor devices in the future.”, explains Ivan Savenko, the leader of the Light-Matter Interaction in Nanostructures (LUMIN) team at the PCS IBS.

    2
    Figure 2. (a) Temperature dependence of the superconducting gap for bogolon-mediated process with temperature correction (dashed) and without temperature correction (solid). (b) The critical temperature of the superconductivity transition as a function of condensate density for bogolon-mediated interaction with (red dashed) and without (black solid) the temperature correction. The blue dash-dotted line shows the BKT transition temperature as a function of the condensate density.

    See the full article here.

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    Stem Education Coalition

    Making Discoveries for Humanity & Society

    Institute for Basic Science [ 기초과학연구원](KR) pursues excellence in basic science research. The goal of IBS is to advance the frontiers of knowledge and to train the leading scientists of tomorrow.

    Accelerate Transformation through New Knowledge

    Institute for Basic Science [ 기초과학연구원](KR) was established in November 2011 as Korea’s first dedicated basic science research institute. By studying the fundamental principles of nature, basic science is essential in creating new knowledge from which significant societal transformations are derived. IBS promotes the highest quality of research that will increase the national basic science capacity and generate new opportunities for this nation.

    IBS specializes in long-term projects that require large groups of researchers. As research in the 21st century requires more interdisciplinary collaborations from larger groups of people, scientists at IBS work together in the same laboratory base with a long-term perspective on research. We promote autonomy in research. IBS believes scientists unleash their creative potential most effectively when they conduct research in an autonomous environment with world-class research infrastructure, including RISP, the rare isotope accelerator, to enable major scientific advances. By developing strong synergies from outstanding talents, autonomous research support systems, and world-class infrastructure, IBS is steadily growing into a major basic research institute that meets the global standards of excellence.
    Ensure Excellence in Research

    By pursuing excellence in research, IBS has selected global leading scientists as directors of Centers. These directors are operating 31 Centers of which research proposals are evaluated superior in the IBS peer review process. The review is carried out by a Review Panel composed of independent and expert scientists from Korea and abroad. Directors choose the themes of their research and allocate funds accordingly. Generally, Centers operate projects with no fixed term for their duration as long as the quality of research is verified in evaluations. New Centers receive an initial evaluation five years after its launch, followed by three-year interval evaluations.

    IBS has been inviting top scientists from around the globe and providing them full support for their relocations. Young scientists also enjoy unique research opportunities to collaborate with world renowned scientists and to organize and operate their own research groups, broadening their professional expertise. IBS brings together outstanding talents throughout all career levels to grow and inspire each other through close collaborations.

    Stimulate Collaboration Without Boundaries

    IBS welcomes scientists from Korea and abroad seeking to work in a collaborative research environment. IBS’ faculty researcher program and IBS’s affiliation with the founding body of University of Science & Technology [과학 기술 연합 대학원대학교] (KR) help IBS scientists to reach out to and foster young talent outside the institution. Centers serve as a catalyst for research collaboration with universities and other government-funded research institutions through joint research and the sharing of research equipment. Other efforts are also underway to stimulate collaborations, including overseas training programs and visiting scientist programs.

    To disseminate research findings, IBS holds “IBS Conferences” and develops a global network with the world’s prominent research institutions including the MPG Society for the Advancement of Science [MPG Gesellschaft zur Förderung der Wissenschaften e. V.] (DE) and the Royal Society (UK). We expect our work to make transformative changes outside as well as inside the institution. To realize this exciting vision, IBS will serve as a national R&D platform and accelerate the creation and use of new knowledge to support universities, research institutions, and businesses. As a driving force for dynamic research collaborations, IBS will continually develop and refresh its science, while always remaining receptive to outside talents and ideas.
    Continue its Endeavor to Make a Brighter Future

    IBS shares the same passion as other great minds to investigate the origin of the universe, nature, and life for the development of humanity, as shown in its vision Masking Discoveries for Humanity & Society. We are committed to realizing this vision through a phased endeavor as outlined in our Five-year Plan (2013 – 2017). We aim to:

    Become a national hub for basic science research by 2017
    Complete the construction of the rare isotope accelerator by 2021
    Evolve into one of the world’s top 20 basic research institution by 2030 (measured in terms of impact on research).

    Serving as a stimulus for the innovation, IBS HQ will evolve into an urban science park that will promote public outreach and community engagement. Our commitment to enhance the quality of life and make sustainable progress continues every day.

     
  • richardmitnick 7:40 pm on July 13, 2021 Permalink | Reply
    Tags: "Custom-made MIT tool probes materials at the nanoscale", , , Condensed Matter Physics, , , , Modern materials research has greatly benefited from advanced experimental tools., , Near-field infrared nanoscope and spectroscope, , Scanning Nearfield Optical Microscope or s-SNOM., Scattering-type scanning nearfield optical microscope   

    From Massachusetts Institute of Technology (US) : “Custom-made MIT tool probes materials at the nanoscale” 

    MIT News

    From Massachusetts Institute of Technology (US)

    July 13, 2021
    Elizabeth A. Thomson

    A scattering-type scanning nearfield optical microscope offers advantages to researchers across many disciplines.

    1
    Assistant Professor Long Ju (center) and colleagues have built a new, customized version of a laboratory tool known as near-field infrared nanoscopy and spectroscopy for MIT users. It and an earlier version, also in Ju’s lab, are the first such tools at the Institute. Here graduate student Matthew Yeung, Professor Ju, and postdoc Zhengguang Lu stand beside the new tool. Credit: Long Ju.

    An MIT physicist has built a new instrument of interest to MIT researchers across a wide range of disciplines because it can quickly and relatively inexpensively determine a variety of important characteristics of a material at the nanoscale. It’s capable of not only determining internal properties of a material, such as how that material’s electrical or optical conductivity changes over exquisitely short distances, but also visualizing individual molecules, like proteins.

    “Modern materials research has greatly benefited from advanced experimental tools,” says Long Ju, an assistant professor in the Department of Physics. Ju is an expert on an emerging instrument that combines nanoscopy — the ability to see things at the nanoscale — with spectroscopy, which probes materials by exploring their interactions with light.

    The tool, known as a near-field infrared nanoscope and spectroscope (it is also known as a scattering-type scanning nearfield optical microscope, or s-SNOM), is available commercially. However, “it’s rather challenging for new users, which limits the applications of the technique,” says Ju.

    So the Ju group built its own version of the tool — the first s-SNOM at MIT — and in May completed a second, more advanced version with additional functions. Now both instruments are available to the MIT community, and the Ju group is on hand to provide assistance to MIT users and to develop new functionalities. Ju encourages MIT colleagues to contact him with potential applications or questions.

    “It’s exciting because it’s a platform that can, in principle, host many different materials systems and extract new information from each,” says Ju, who is also affiliated with MIT’s Materials Research Laboratory. “It’s also a platform for some of the best minds in the world — MIT researchers — to conceive things beyond what can be done on a standard s-SNOM.”

    The new tool is based on atomic force microscopy (AFM), in which an extremely sharp metallic tip with a radius of only 20 nanometers, or billionths of a meter, is scanned across the surface of a material. AFM creates a map of the physical features, or topography, of a surface, of such high resolution that it can identify “mountains” or “valleys” less than a nanometer in height or depth.

    Adding light

    Ju is adding light to the equation. Focusing an infrared laser on the AFM tip turns that tip into an antenna “just like the antenna on a television that’s used to receive signals,” he says. And that, in turn, greatly enhances interactions between the light and the material beneath the tip. The back-scattered light collected from those interactions can be analyzed to reveal much more about the surface than would be possible with a conventional AFM.

    The result: “You can get an image of your sample with three orders of magnitude better spatial resolution than that of conventional infrared measurements,” says Ju. In earlier work reported in Nature, he and colleagues published images of graphene taken with AFM and with the new tool. There are features in common between the two, but the near-field image is riddled with bright lines that are not visible in the AFM image. They are domain walls, or the interfaces between two different sections of a material. Those interfaces are key to understanding a material’s structure and properties.

    Images of similar detail can be captured with transmission electron microscopy (TEM), but TEM has some drawbacks. For example, it must be operated in an ultra-high vacuum, and samples must be extremely thin for suspension on a film or membrane. “The former limits the experimental throughput, while the latter is not compatible with most materials,” says Ju.

    In contrast, the near-field nanoscope “can be operated in air, does not require suspension of the sample, and you can work on most solid substrates,” Ju says.

    Many applications

    Ju notes that the near-field tool can not only provide high-resolution images of heights; the analysis of back-scattered light from the machine’s tip can also give important information about a material’s internal properties. For example, it can tell metals from insulators. It can also distinguish between materials with the same chemical composition but different internal structures (think diamond versus pencil lead).

    In an example he describes as “especially cool,” Ju says that the instrument could even be used to watch a material transition from insulator to superconductor as the temperature is changed. It is also capable of monitoring chemical reactions on the nanoscale.

    Ju also notes that the new tool can be operated in different ways for different purposes. For example, he said, the tip of the tool can either be scanned across a surface while being irradiated with a set wavelength of light, or the tip can be parked over a certain area and probed with light of different wavelengths. Different wavelengths of light interact differently with different materials, giving even more information about a given material’s composition or other characteristics.

    Ju, who came to MIT in 2019, is thoroughly enjoying meeting other MIT researchers who might have applications for his machine. “It’s exciting to work with people from different research areas. You can work together to generate new ideas at the cutting edge.”

    This work is sponsored by MIT’s Materials Research Laboratory.

    See the full article here .


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    MIT Seal

    USPS “Forever” postage stamps celebrating Innovation at MIT.

    MIT Campus

    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, the Bates Center, and the Haystack Observatory, as well as affiliated laboratories such as the Broad and Whitehead Institutes.

    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 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) .

    MIT/Caltech 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 (US) community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

     
  • richardmitnick 8:47 pm on July 12, 2021 Permalink | Reply
    Tags: "Discovery of 10 faces of plasma leads to new insights in fusion and plasma science", Condensed Matter Physics, , The localized plasma waves produced by phase transitions are robust and intrinsic because they are “topologically protected.”, The next step is to explore what these excitations could do and how they might be utilized., The plasma phases that PPPL has uncovered are technically known as “topological phases” indicating the shapes of the waves supported by plasma., The spatial boundaries or transitions between different phases will support localized wave excitations the researchers found.   

    From DOE’s Princeton Plasma Physics Laboratory (US) : “Discovery of 10 faces of plasma leads to new insights in fusion and plasma science” 

    From DOE’s Princeton Plasma Physics Laboratory (US)

    July 12, 2021
    John Greenwald

    1
    Physicists Hong Qin, left, and Yichen Fu, with rendering of 10 phases of plasma from their Nature Communications paper. Photos and collage by Elle Starkman/Office of Communications.

    Scientists have discovered a novel way to classify magnetized plasmas that could possibly lead to advances in harvesting on Earth the fusion energy that powers the sun and stars. The discovery by theorists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) found that a magnetized plasma has 10 unique phases and the transitions between them might hold rich implications for practical development.

    The spatial boundaries or transitions between different phases will support localized wave excitations the researchers found. “These findings could lead to possible applications of these exotic excitations in space and laboratory plasmas,” said Yichen Fu, a graduate student at PPPL and lead author of a paper in Nature Communications that outlines the research. “The next step is to explore what these excitations could do and how they might be utilized.”

    Possible applications

    Possible applications include using the excitations to create current in magnetic fusion plasmas or facilitating plasma rotation in fusion experiments. However, “Our paper doesn’t consider any practical applications,” said physicist Hong Qin, co-author of the paper and Fu’s advisor. “The paper is the basic theory and the technology will follow the theoretical understanding.”

    In fact, “the discovery of the 10 phases in plasma marks a primary development in plasma physics,” Qin said. “The first and foremost step in any scientific endeavor is to classify the objects under investigation. Any new classification scheme will lead to improvement in our theoretical understanding and subsequent advances in technology,” he said.

    Qin cites discovery of the major types of diabetes as an example of the role classification plays in scientific progress. “When developing treatments for diabetes, scientists found that there were three major types,” he said. “Now medical practitioners can effectively treat diabetic patients.”

    Fusion, which scientists around the world are seeking to produce on Earth, combines light elements in the form of plasma — the hot, charged state of matter composed of free electrons and atomic nuclei that makes up 99 percent of the visible universe — to release massive amounts of energy. Such energy could serve as a safe and clean source of power for generating electricity.

    The plasma phases that PPPL has uncovered are technically known as “topological phases” indicating the shapes of the waves supported by plasma. This unique property of matter was first discovered in the discipline of condensed matter physics during the 1970s — a discovery for which physicist Duncan Haldane of Princeton University shared the 2016 Nobel Prize for his pioneering work.

    Robust and intrinsic

    The localized plasma waves produced by phase transitions are robust and intrinsic because they are “topologically protected,” Qin said. “The discovery that this topologically protected excitation exists in magnetized plasmas is a big step forward that can be explored for practical applications,” he said.

    For first author Fu, “The most important progress in the paper is looking at plasma based on its topological properties and identifying its topological phases. Based on these phases we identify the necessary and sufficient condition for the excitations of these localized waves. As for how this progress can be applied to facilitate fusion energy research, we have to find out.”

    See the full article here .


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    PPPL campus

    Princeton Plasma Physics Laboratory (US) is a U.S. Department of Energy national laboratory managed by Princeton University. PPPL, on Princeton University’s Forrestal Campus in Plainsboro, N.J., is devoted to creating new knowledge about the physics of plasmas — ultra-hot, charged gases — and to developing practical solutions for the creation of fusion energy. Results of PPPL research have ranged from a portable nuclear materials detector for anti-terrorist use to universally employed computer codes for analyzing and predicting the outcome of fusion experiments. The Laboratory is managed by the University for the U.S. Department of Energy’s Office of Science, which is the largest single 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. For more information, please visit https://energy.gov/science.

    Princeton University

    Princeton University
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    About Princeton: Overview

    Princeton University is a private Ivy League research university in Princeton, New Jersey(US). Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the nine colonial colleges chartered before the American Revolution. The institution moved to Newark in 1747, then to the current site nine years later. It was renamed Princeton University in 1896.

    Princeton provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences, and engineering. It offers professional degrees through the Princeton School of Public and International Affairs, the School of Engineering and Applied Science, the School of Architecture and the Bendheim Center for Finance. The university also manages the DOE’s Princeton Plasma Physics Laboratory. Princeton has the largest endowment per student in the United States.

    As of October 2020, 69 Nobel laureates, 15 Fields Medalists and 14 Turing Award laureates have been affiliated with Princeton University as alumni, faculty members or researchers. In addition, Princeton has been associated with 21 National Medal of Science winners, 5 Abel Prize winners, 5 National Humanities Medal recipients, 215 Rhodes Scholars, 139 Gates Cambridge Scholars and 137 Marshall Scholars. Two U.S. Presidents, twelve U.S. Supreme Court Justices (three of whom currently serve on the court) and numerous living billionaires and foreign heads of state are all counted among Princeton’s alumni body. Princeton has also graduated many prominent members of the U.S. Congress and the U.S. Cabinet, including eight Secretaries of State, three Secretaries of Defense and the current Chairman of the Joint Chiefs of Staff.

    Princeton University, founded as the College of New Jersey, was considered the successor of the “Log College” founded by the Reverend William Tennent at Neshaminy, PA in about 1726. New Light Presbyterians founded the College of New Jersey in 1746 in Elizabeth, New Jersey. Its purpose was to train ministers. The college was the educational and religious capital of Scottish Presbyterian America. Unlike Harvard University(US), which was originally “intensely English” with graduates taking the side of the crown during the American Revolution, Princeton was founded to meet the religious needs of the period and many of its graduates took the American side in the war. In 1754, trustees of the College of New Jersey suggested that, in recognition of Governor Jonathan Belcher’s interest, Princeton should be named as Belcher College. Belcher replied: “What a name that would be!” In 1756, the college moved its campus to Princeton, New Jersey. Its home in Princeton was Nassau Hall, named for the royal House of Orange-Nassau of William III of England.

    Following the untimely deaths of Princeton’s first five presidents, John Witherspoon became president in 1768 and remained in that post until his death in 1794. During his presidency, Witherspoon shifted the college’s focus from training ministers to preparing a new generation for secular leadership in the new American nation. To this end, he tightened academic standards and solicited investment in the college. Witherspoon’s presidency constituted a long period of stability for the college, interrupted by the American Revolution and particularly the Battle of Princeton, during which British soldiers briefly occupied Nassau Hall; American forces, led by George Washington, fired cannon on the building to rout them from it.

    In 1812, the eighth president of the College of New Jersey, Ashbel Green (1812–23), helped establish the Princeton Theological Seminary next door. The plan to extend the theological curriculum met with “enthusiastic approval on the part of the authorities at the College of New Jersey.” Today, Princeton University and Princeton Theological Seminary maintain separate institutions with ties that include services such as cross-registration and mutual library access.

    Before the construction of Stanhope Hall in 1803, Nassau Hall was the college’s sole building. The cornerstone of the building was laid on September 17, 1754. During the summer of 1783, the Continental Congress met in Nassau Hall, making Princeton the country’s capital for four months. Over the centuries and through two redesigns following major fires (1802 and 1855), Nassau Hall’s role shifted from an all-purpose building, comprising office, dormitory, library, and classroom space; to classroom space exclusively; to its present role as the administrative center of the University. The class of 1879 donated twin lion sculptures that flanked the entrance until 1911, when that same class replaced them with tigers. Nassau Hall’s bell rang after the hall’s construction; however, the fire of 1802 melted it. The bell was then recast and melted again in the fire of 1855.

    James McCosh became the college’s president in 1868 and lifted the institution out of a low period that had been brought about by the American Civil War. During his two decades of service, he overhauled the curriculum, oversaw an expansion of inquiry into the sciences, and supervised the addition of a number of buildings in the High Victorian Gothic style to the campus. McCosh Hall is named in his honor.

    In 1879, the first thesis for a Doctor of Philosophy (Ph.D.) was submitted by James F. Williamson, Class of 1877.

    In 1896, the college officially changed its name from the College of New Jersey to Princeton University to honor the town in which it resides. During this year, the college also underwent large expansion and officially became a university. In 1900, the Graduate School was established.

    In 1902, Woodrow Wilson, graduate of the Class of 1879, was elected the 13th president of the university. Under Wilson, Princeton introduced the preceptorial system in 1905, a then-unique concept in the United States that augmented the standard lecture method of teaching with a more personal form in which small groups of students, or precepts, could interact with a single instructor, or preceptor, in their field of interest.

    In 1906, the reservoir Carnegie Lake was created by Andrew Carnegie. A collection of historical photographs of the building of the lake is housed at the Seeley G. Mudd Manuscript Library on Princeton’s campus. On October 2, 1913, the Princeton University Graduate College was dedicated. In 1919 the School of Architecture was established. In 1933, Albert Einstein became a lifetime member of the Institute for Advanced Study with an office on the Princeton campus. While always independent of the university, the Institute for Advanced Study occupied offices in Jones Hall for 6 years, from its opening in 1933, until its own campus was finished and opened in 1939.

    Coeducation

    In 1969, Princeton University first admitted women as undergraduates. In 1887, the university actually maintained and staffed a sister college, Evelyn College for Women, in the town of Princeton on Evelyn and Nassau streets. It was closed after roughly a decade of operation. After abortive discussions with Sarah Lawrence College to relocate the women’s college to Princeton and merge it with the University in 1967, the administration decided to admit women and turned to the issue of transforming the school’s operations and facilities into a female-friendly campus. The administration had barely finished these plans in April 1969 when the admissions office began mailing out its acceptance letters. Its five-year coeducation plan provided $7.8 million for the development of new facilities that would eventually house and educate 650 women students at Princeton by 1974. Ultimately, 148 women, consisting of 100 freshmen and transfer students of other years, entered Princeton on September 6, 1969 amidst much media attention. Princeton enrolled its first female graduate student, Sabra Follett Meservey, as a PhD candidate in Turkish history in 1961. A handful of undergraduate women had studied at Princeton from 1963 on, spending their junior year there to study “critical languages” in which Princeton’s offerings surpassed those of their home institutions. They were considered regular students for their year on campus, but were not candidates for a Princeton degree.

    As a result of a 1979 lawsuit by Sally Frank, Princeton’s eating clubs were required to go coeducational in 1991, after Tiger Inn’s appeal to the U.S. Supreme Court was denied. In 1987, the university changed the gendered lyrics of “Old Nassau” to reflect the school’s co-educational student body. From 2009 to 2011, Princeton professor Nannerl O. Keohane chaired a committee on undergraduate women’s leadership at the university, appointed by President Shirley M. Tilghman.

    The main campus sits on about 500 acres (2.0 km^2) in Princeton. In 2011, the main campus was named by Travel+Leisure as one of the most beautiful in the United States. The James Forrestal Campus is split between nearby Plainsboro and South Brunswick. The University also owns some property in West Windsor Township. The campuses are situated about one hour from both New York City and Philadelphia.

    The first building on campus was Nassau Hall, completed in 1756 and situated on the northern edge of campus facing Nassau Street. The campus expanded steadily around Nassau Hall during the early and middle 19th century. The McCosh presidency (1868–88) saw the construction of a number of buildings in the High Victorian Gothic and Romanesque Revival styles; many of them are now gone, leaving the remaining few to appear out of place. At the end of the 19th century much of Princeton’s architecture was designed by the Cope and Stewardson firm (same architects who designed a large part of Washington University in St Louis (US) and University of Pennsylvania(US)) resulting in the Collegiate Gothic style for which it is known today. Implemented initially by William Appleton Potter and later enforced by the University’s supervising architect, Ralph Adams Cram, the Collegiate Gothic style remained the standard for all new building on the Princeton campus through 1960. A flurry of construction in the 1960s produced a number of new buildings on the south side of the main campus, many of which have been poorly received. Several prominent architects have contributed some more recent additions, including Frank Gehry (Lewis Library), I. M. Pei (Spelman Halls), Demetri Porphyrios (Whitman College, a Collegiate Gothic project), Robert Venturi and Denise Scott Brown (Frist Campus Center, among several others), and Rafael Viñoly (Carl Icahn Laboratory).

    A group of 20th-century sculptures scattered throughout the campus forms the Putnam Collection of Sculpture. It includes works by Alexander Calder (Five Disks: One Empty), Jacob Epstein (Albert Einstein), Henry Moore (Oval with Points), Isamu Noguchi (White Sun), and Pablo Picasso (Head of a Woman). Richard Serra’s The Hedgehog and The Fox is located between Peyton and Fine halls next to Princeton Stadium and the Lewis Library.

    At the southern edge of the campus is Carnegie Lake, an artificial lake named for Andrew Carnegie. Carnegie financed the lake’s construction in 1906 at the behest of a friend who was a Princeton alumnus. Carnegie hoped the opportunity to take up rowing would inspire Princeton students to forsake football, which he considered “not gentlemanly.” The Shea Rowing Center on the lake’s shore continues to serve as the headquarters for Princeton rowing.

    Cannon Green

    Buried in the ground at the center of the lawn south of Nassau Hall is the “Big Cannon,” which was left in Princeton by British troops as they fled following the Battle of Princeton. It remained in Princeton until the War of 1812, when it was taken to New Brunswick. In 1836 the cannon was returned to Princeton and placed at the eastern end of town. It was removed to the campus under cover of night by Princeton students in 1838 and buried in its current location in 1840.

    A second “Little Cannon” is buried in the lawn in front of nearby Whig Hall. This cannon, which may also have been captured in the Battle of Princeton, was stolen by students of Rutgers University in 1875. The theft ignited the Rutgers-Princeton Cannon War. A compromise between the presidents of Princeton and Rutgers ended the war and forced the return of the Little Cannon to Princeton. The protruding cannons are occasionally painted scarlet by Rutgers students who continue the traditional dispute.

    In years when the Princeton football team beats the teams of both Harvard University and Yale University in the same season, Princeton celebrates with a bonfire on Cannon Green. This occurred in 2012, ending a five-year drought. The next bonfire happened on November 24, 2013, and was broadcast live over the Internet.

    Landscape

    Princeton’s grounds were designed by Beatrix Farrand between 1912 and 1943. Her contributions were most recently recognized with the naming of a courtyard for her. Subsequent changes to the landscape were introduced by Quennell Rothschild & Partners in 2000. In 2005, Michael Van Valkenburgh was hired as the new consulting landscape architect for the campus. Lynden B. Miller was invited to work with him as Princeton’s consulting gardening architect, focusing on the 17 gardens that are distributed throughout the campus.

    Buildings

    Nassau Hall

    Nassau Hall is the oldest building on campus. Begun in 1754 and completed in 1756, it was the first seat of the New Jersey Legislature in 1776, was involved in the battle of Princeton in 1777, and was the seat of the Congress of the Confederation (and thus capitol of the United States) from June 30, 1783, to November 4, 1783. It now houses the office of the university president and other administrative offices, and remains the symbolic center of the campus. The front entrance is flanked by two bronze tigers, a gift of the Princeton Class of 1879. Commencement is held on the front lawn of Nassau Hall in good weather. In 1966, Nassau Hall was added to the National Register of Historic Places.

    Residential colleges

    Princeton has six undergraduate residential colleges, each housing approximately 500 freshmen, sophomores, some juniors and seniors, and a handful of junior and senior resident advisers. Each college consists of a set of dormitories, a dining hall, a variety of other amenities—such as study spaces, libraries, performance spaces, and darkrooms—and a collection of administrators and associated faculty. Two colleges, First College and Forbes College (formerly Woodrow Wilson College and Princeton Inn College, respectively), date to the 1970s; three others, Rockefeller, Mathey, and Butler Colleges, were created in 1983 following the Committee on Undergraduate Residential Life (CURL) report, which suggested the institution of residential colleges as a solution to an allegedly fragmented campus social life. The construction of Whitman College, the university’s sixth residential college, was completed in 2007.

    Rockefeller and Mathey are located in the northwest corner of the campus; Princeton brochures often feature their Collegiate Gothic architecture. Like most of Princeton’s Gothic buildings, they predate the residential college system and were fashioned into colleges from individual dormitories.

    First and Butler, located south of the center of the campus, were built in the 1960s. First served as an early experiment in the establishment of the residential college system. Butler, like Rockefeller and Mathey, consisted of a collection of ordinary dorms (called the “New New Quad”) before the addition of a dining hall made it a residential college. Widely disliked for their edgy modernist design, including “waffle ceilings,” the dormitories on the Butler Quad were demolished in 2007. Butler is now reopened as a four-year residential college, housing both under- and upperclassmen.

    Forbes is located on the site of the historic Princeton Inn, a gracious hotel overlooking the Princeton golf course. The Princeton Inn, originally constructed in 1924, played regular host to important symposia and gatherings of renowned scholars from both the university and the nearby Institute for Advanced Study for many years. Forbes currently houses nearly 500 undergraduates in its residential halls.

    In 2003, Princeton broke ground for a sixth college named Whitman College after its principal sponsor, Meg Whitman, who graduated from Princeton in 1977. The new dormitories were constructed in the Collegiate Gothic architectural style and were designed by architect Demetri Porphyrios. Construction finished in 2007, and Whitman College was inaugurated as Princeton’s sixth residential college that same year.

    The precursor of the present college system in America was originally proposed by university president Woodrow Wilson in the early 20th century. For over 800 years, however, the collegiate system had already existed in Britain at Cambridge and Oxford Universities. Wilson’s model was much closer to Yale University(US)’s present system, which features four-year colleges. Lacking the support of the trustees, the plan languished until 1968. That year, Wilson College was established to cap a series of alternatives to the eating clubs. Fierce debates raged before the present residential college system emerged. The plan was first attempted at Yale, but the administration was initially uninterested; an exasperated alumnus, Edward Harkness, finally paid to have the college system implemented at Harvard in the 1920s, leading to the oft-quoted aphorism that the college system is a Princeton idea that was executed at Harvard with funding from Yale.

    Princeton has one graduate residential college, known simply as the Graduate College, located beyond Forbes College at the outskirts of campus. The far-flung location of the GC was the spoil of a squabble between Woodrow Wilson and then-Graduate School Dean Andrew Fleming West. Wilson preferred a central location for the college; West wanted the graduate students as far as possible from the campus. Ultimately, West prevailed. The Graduate College is composed of a large Collegiate Gothic section crowned by Cleveland Tower, a local landmark that also houses a world-class carillon. The attached New Graduate College provides a modern contrast in architectural style.

    McCarter Theatre

    The Tony-award-winning McCarter Theatre was built by the Princeton Triangle Club, a student performance group, using club profits and a gift from Princeton University alumnus Thomas McCarter. Today, the Triangle Club performs its annual freshmen revue, fall show, and Reunions performances in McCarter. McCarter is also recognized as one of the leading regional theaters in the United States.

    Art Museum

    The Princeton University Art Museum was established in 1882 to give students direct, intimate, and sustained access to original works of art that complement and enrich instruction and research at the university. This continues to be a primary function, along with serving as a community resource and a destination for national and international visitors.

    Numbering over 92,000 objects, the collections range from ancient to contemporary art and concentrate geographically on the Mediterranean regions, Western Europe, China, the United States, and Latin America. There is a collection of Greek and Roman antiquities, including ceramics, marbles, bronzes, and Roman mosaics from faculty excavations in Antioch. Medieval Europe is represented by sculpture, metalwork, and stained glass. The collection of Western European paintings includes examples from the early Renaissance through the 19th century, with masterpieces by Monet, Cézanne, and Van Gogh, and features a growing collection of 20th-century and contemporary art, including iconic paintings such as Andy Warhol’s Blue Marilyn.

    One of the best features of the museums is its collection of Chinese art, with important holdings in bronzes, tomb figurines, painting, and calligraphy. Its collection of pre-Columbian art includes examples of Mayan art, and is commonly considered to be the most important collection of pre-Columbian art outside of Latin America. The museum has collections of old master prints and drawings and a comprehensive collection of over 27,000 original photographs. African art and Northwest Coast Indian art are also represented. The Museum also oversees the outdoor Putnam Collection of Sculpture.

    University Chapel

    The Princeton University Chapel is located on the north side of campus, near Nassau Street. It was built between 1924 and 1928, at a cost of $2.3 million [approximately $34.2 million in 2020 dollars]. Ralph Adams Cram, the University’s supervising architect, designed the chapel, which he viewed as the crown jewel for the Collegiate Gothic motif he had championed for the campus. At the time of its construction, it was the second largest university chapel in the world, after King’s College Chapel, Cambridge. It underwent a two-year, $10 million restoration campaign between 2000 and 2002.

    Measured on the exterior, the chapel is 277 feet (84 m) long, 76 feet (23 m) wide at its transepts, and 121 feet (37 m) high. The exterior is Pennsylvania sandstone, with Indiana limestone used for the trim. The interior is mostly limestone and Aquia Creek sandstone. The design evokes an English church of the Middle Ages. The extensive iconography, in stained glass, stonework, and wood carvings, has the common theme of connecting religion and scholarship.

    The Chapel seats almost 2,000. It hosts weekly ecumenical Christian services, daily Roman Catholic mass, and several annual special events.

    Murray-Dodge Hall

    Murray-Dodge Hall houses the Office of Religious Life (ORL), the Murray Dodge Theater, the Murray-Dodge Café, the Muslim Prayer Room and the Interfaith Prayer Room. The ORL houses the office of the Dean of Religious Life, Alison Boden, and a number of university chaplains, including the country’s first Hindu chaplain, Vineet Chander; and one of the country’s first Muslim chaplains, Sohaib Sultan.

    Sustainability

    Published in 2008, Princeton’s Sustainability Plan highlights three priority areas for the University’s Office of Sustainability: reduction of greenhouse gas emissions; conservation of resources; and research, education, and civic engagement. Princeton has committed to reducing its carbon dioxide emissions to 1990 levels by 2020: Energy without the purchase of offsets. The University published its first Sustainability Progress Report in November 2009. The University has adopted a green purchasing policy and recycling program that focuses on paper products, construction materials, lightbulbs, furniture, and electronics. Its dining halls have set a goal to purchase 75% sustainable food products by 2015. The student organization “Greening Princeton” seeks to encourage the University administration to adopt environmentally friendly policies on campus.

    Organization

    The Trustees of Princeton University, a 40-member board, is responsible for the overall direction of the University. It approves the operating and capital budgets, supervises the investment of the University’s endowment and oversees campus real estate and long-range physical planning. The trustees also exercise prior review and approval concerning changes in major policies, such as those in instructional programs and admission, as well as tuition and fees and the hiring of faculty members.

    With an endowment of $26.1 billion, Princeton University is among the wealthiest universities in the world. Ranked in 2010 as the third largest endowment in the United States, the university had the greatest per-student endowment in the world (over $2 million for undergraduates) in 2011. Such a significant endowment is sustained through the continued donations of its alumni and is maintained by investment advisers. Some of Princeton’s wealth is invested in its art museum, which features works by Claude Monet, Vincent van Gogh, Jackson Pollock, and Andy Warhol among other prominent artists.

    Academics

    Undergraduates fulfill general education requirements, choose among a wide variety of elective courses, and pursue departmental concentrations and interdisciplinary certificate programs. Required independent work is a hallmark of undergraduate education at Princeton. Students graduate with either the Bachelor of Arts (A.B.) or the Bachelor of Science in Engineering (B.S.E.).

    The graduate school offers advanced degrees spanning the humanities, social sciences, natural sciences, and engineering. Doctoral education is available in most disciplines. It emphasizes original and independent scholarship whereas master’s degree programs in architecture, engineering, finance, and public affairs and public policy prepare candidates for careers in public life and professional practice.

    The university has ties with the Institute for Advanced Study, Princeton Theological Seminary and the Westminster Choir College of Rider University(US).

    Undergraduate

    Undergraduate courses in the humanities are traditionally either seminars or lectures held 2 or 3 times a week with an additional discussion seminar that is called a “precept.” To graduate, all A.B. candidates must complete a senior thesis and, in most departments, one or two extensive pieces of independent research that are known as “junior papers.” Juniors in some departments, including architecture and the creative arts, complete independent projects that differ from written research papers. A.B. candidates must also fulfill a three or four semester foreign language requirement and distribution requirements (which include, for example, classes in ethics, literature and the arts, and historical analysis) with a total of 31 classes. B.S.E. candidates follow a parallel track with an emphasis on a rigorous science and math curriculum, a computer science requirement, and at least two semesters of independent research including an optional senior thesis. All B.S.E. students must complete at least 36 classes. A.B. candidates typically have more freedom in course selection than B.S.E. candidates because of the fewer number of required classes. Nonetheless, in the spirit of a liberal arts education, both enjoy a comparatively high degree of latitude in creating a self-structured curriculum.

    Undergraduates agree to adhere to an academic integrity policy called the Honor Code, established in 1893. Under the Honor Code, faculty do not proctor examinations; instead, the students proctor one another and must report any suspected violation to an Honor Committee made up of undergraduates. The Committee investigates reported violations and holds a hearing if it is warranted. An acquittal at such a hearing results in the destruction of all records of the hearing; a conviction results in the student’s suspension or expulsion. The signed pledge required by the Honor Code is so integral to students’ academic experience that the Princeton Triangle Club performs a song about it each fall. Out-of-class exercises fall under the jurisdiction of the Faculty-Student Committee on Discipline. Undergraduates are expected to sign a pledge on their written work affirming that they have not plagiarized the work.

    Graduate

    The Graduate School has about 2,600 students in 42 academic departments and programs in social sciences; engineering; natural sciences; and humanities. These departments include the Department of Psychology; Department of History; and Department of Economics.

    In 2017–2018, it received nearly 11,000 applications for admission and accepted around 1,000 applicants. The University also awarded 319 Ph.D. degrees and 170 final master’s degrees. Princeton has no medical school, law school, business school, or school of education. (A short-lived Princeton Law School folded in 1852.) It offers professional graduate degrees in architecture; engineering; finance and public policy- the last through the Princeton School of Public and International Affairs founded in 1930 as the School of Public and International Affairs and renamed in 1948 after university president (and U.S. president) Woodrow Wilson, and most recently renamed in 2020.

    Libraries

    The Princeton University Library system houses over eleven million holdings including seven million bound volumes. The main university library, Firestone Library, which houses almost four million volumes, is one of the largest university libraries in the world. Additionally, it is among the largest “open stack” libraries in existence. Its collections include the autographed manuscript of F. Scott Fitzgerald’s The Great Gatsby and George F. Kennan’s Long Telegram. In addition to Firestone library, specialized libraries exist for architecture, art and archaeology, East Asian studies, engineering, music, public and international affairs, public policy and university archives, and the sciences. In an effort to expand access, these libraries also subscribe to thousands of electronic resources.

    Institutes

    High Meadows Environmental Institute

    The High Meadows Environmental Institute is an “interdisciplinary center of environmental research, education, and outreach” at the university. The institute was started in 1994. About 90 faculty members at Princeton University are affiliated with it.

    The High Meadows Environmental Institute has the following research centers:

    Carbon Mitigation Initiative (CMI): This is a 15-year-long partnership between PEI and British Petroleum with the goal of finding solutions to problems related to climate change. The Stabilization Wedge Game has been created as part of this initiative.
    Center for BioComplexity (CBC)
    Cooperative Institute for Climate Science (CICS): This is a collaboration with the National Oceanographic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory.
    Energy Systems Analysis Group
    Grand Challenges

     
  • richardmitnick 7:53 pm on April 21, 2021 Permalink | Reply
    Tags: , Condensed Matter Physics, , , PDW's-pair density waves, , RSXS-resonant soft X-ray scattering, , , The existence of the PDW phase in high-temperature superconductors was proposed more than a decade ago and it’s become an exciting area of research.,   

    From DOE’s SLAC National Accelerator Laboratory (US): “Scientists glimpse signs of a puzzling state of matter in a superconductor with SSRL” 

    From DOE’s SLAC National Accelerator Laboratory (US)

    April 21, 2021
    Glennda Chui

    1
    SLAC scientists used an improved X-ray technique to explore exotic states of matter in an unconventional superconductor that conducts electricity with 100% efficiency at relatively high temperatures. They glimpsed the signature of a state known as pair density waves (PDW), and confirmed that it intertwines with another phase known as charge density wave (CDW) stripes – wavelike patterns of higher and lower electron density in the material. CDWs, in turn, are created when spin density waves (SDWs) emerge and intertwine. Credit: Jun-Sik Lee/SLAC National Accelerator Laboratory.

    Known as “pair-density waves,” it may be key to understanding how superconductivity can exist at relatively high temperatures.

    Unconventional superconductors contain a number of exotic phases of matter that are thought to play a role, for better or worse, in their ability to conduct electricity with 100% efficiency at much higher temperatures than scientists had thought possible – although still far short of the temperatures that would allow their wide deployment in perfectly efficient power lines, maglev trains and so on.

    Now scientists at the Department of Energy’s SLAC National Accelerator Laboratory have glimpsed the signature of one of those phases, known as pair-density waves or PDW, and confirmed that it’s intertwined with another phase known as charge density wave (CDW) stripes – wavelike patterns of higher and lower electron density in the material.

    Observing and understanding PDW and its correlations with other phases may be essential for understanding how superconductivity emerges in these materials, allowing electrons to pair up and travel with no resistance, said Jun-Sik Lee, a SLAC staff scientist who led the research at the lab’s Stanford Synchrotron Radiation Lightsource (SSRL).

    Even indirect evidence of the PDW phase intertwined with charge stripes, he said, is an important step on the long road toward understanding the mechanism behind unconventional superconductivity, which has eluded scientists over more than 30 years of research.

    Lee added that the method his team used to make this observation, which involved dramatically increasing the sensitivity of a standard X-ray technique known as resonant soft X-ray scattering (RSXS) so it could see the extremely faint signals given off by these phenomena, has potential for directly sighting both the PDW signature and its correlations with other phases in future experiments. That’s what they plan to work on next.

    The scientists described their findings today in Physical Review Letters.

    Untangling superconductor secrets

    The existence of the PDW phase in high-temperature superconductors was proposed more than a decade ago and it’s become an exciting area of research, with theorists developing models to explain how it works and experimentalists searching for it in a variety of materials.

    In this study, the researchers went looking for it in a copper oxide, or cuprate, material known as LSCFO for the elements it contains ­– lanthanum, strontium, copper, iron and oxygen. It’s thought to host two other phases that may intertwine with PDW: charge density wave stripes and spin density wave stripes.

    The nature and behavior of charge and spin stripes have been explored in a number of studies, but there had been only a few indirect glimpses of PDW – much like identifying an animal from its tracks – and none made with X-ray scattering techniques. Because X-ray scattering reveals the behavior of an entire sample at once, it’s thought to be the most promising way to clarify whether PDW exists and how it relates to other key phases in cuprates, Lee said.

    Over the past few years, the SSRL team has worked on increasing the sensitivity of RSXS so it could capture the signals they were looking for.

    Postdoctoral researcher Hai Huang and SLAC staff engineer Sang-Jun Lee used the improved technique in this study. They scattered X-rays off LSCFO and into a detector, forming patterns that revealed what was going on inside the material. As they dropped the temperature of the material toward its superconducting range, spin stripes appeared and intertwined to form charge stripes, and those charge stripes were then associated with the emergence of two-dimensional fluctuations that are the hallmark of PDW.

    The researchers said these results not only demonstrate the value of the new RSXS approach, but also support the possibility that the PDW is present not just in this material, but in all of the superconducting cuprates.

    A research team led by Masaki Fujita at Tohoku University (東北大学, Tōhoku daigaku) (JP) in Japan grew the high-quality LSCFO crystal used in the experiment and conducted preliminary tests on it there. The research was funded by the DOE Office of Science. SSRL is a DOE Office of Science user facility.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    SLAC National Accelerator Laboratory (US) originally named Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Department of Energy Office of Science and located in Menlo Park, California. It is the site of the Stanford Linear Accelerator, a 3.2 kilometer (2-mile) linear accelerator constructed in 1966 and shut down in the 2000s, which could accelerate electrons to energies of 50 GeV.

    Today SLAC research centers on a broad program in atomic and solid-state physics, chemistry, biology, and medicine using X-rays from synchrotron radiation and a free-electron laser as well as experimental and theoretical research in elementary particle physics, astroparticle physics, and cosmology.

    Founded in 1962 as the Stanford Linear Accelerator Center, the facility is located on 172 hectares (426 acres) of Stanford University-owned land on Sand Hill Road in Menlo Park, California—just west of the University’s main campus. The main accelerator is 3.2 kilometers (2 mi) long—the longest linear accelerator in the world—and has been operational since 1966.

    Research at SLAC has produced three Nobel Prizes in Physics

    1976: The charm quark—see J/ψ meson
    1990: Quark structure inside protons and neutrons
    1995: The tau lepton

    SLAC’s meeting facilities also provided a venue for the Homebrew Computer Club and other pioneers of the home computer revolution of the late 1970s and early 1980s.

    In 1984 the laboratory was named an ASME National Historic Engineering Landmark and an IEEE Milestone.

    SLAC developed and, in December 1991, began hosting the first World Wide Web server outside of Europe.

    In the early-to-mid 1990s, the Stanford Linear Collider (SLC) investigated the properties of the Z boson using the Stanford Large Detector.

    As of 2005, SLAC employed over 1,000 people, some 150 of whom were physicists with doctorate degrees, and served over 3,000 visiting researchers yearly, operating particle accelerators for high-energy physics and the Stanford Synchrotron Radiation Laboratory (SSRL) for synchrotron light radiation research, which was “indispensable” in the research leading to the 2006 Nobel Prize in Chemistry awarded to Stanford Professor Roger D. Kornberg.

    In October 2008, the Department of Energy announced that the center’s name would be changed to SLAC National Accelerator Laboratory. The reasons given include a better representation of the new direction of the lab and the ability to trademark the laboratory’s name. Stanford University had legally opposed the Department of Energy’s attempt to trademark “Stanford Linear Accelerator Center”.

    In March 2009, it was announced that the SLAC National Accelerator Laboratory was to receive $68.3 million in Recovery Act Funding to be disbursed by Department of Energy’s Office of Science.

    In October 2016, Bits and Watts launched as a collaboration between SLAC and Stanford University to design “better, greener electric grids”. SLAC later pulled out over concerns about an industry partner, the state-owned Chinese electric utility.

    Accelerator

    The main accelerator was an RF linear accelerator that accelerated electrons and positrons up to 50 GeV. At 3.2 km (2.0 mi) long, the accelerator was the longest linear accelerator in the world, and was claimed to be “the world’s most straight object.” until 2017 when the European x-ray free electron laser opened. The main accelerator is buried 9 m (30 ft) below ground and passes underneath Interstate Highway 280. The above-ground klystron gallery atop the beamline, was the longest building in the United States until the LIGO project’s twin interferometers were completed in 1999. It is easily distinguishable from the air and is marked as a visual waypoint on aeronautical charts.

    A portion of the original linear accelerator is now part of the Linac Coherent Light Source [below].

    Stanford Linear Collider

    The Stanford Linear Collider was a linear accelerator that collided electrons and positrons at SLAC. The center of mass energy was about 90 GeV, equal to the mass of the Z boson, which the accelerator was designed to study. Grad student Barrett D. Milliken discovered the first Z event on 12 April 1989 while poring over the previous day’s computer data from the Mark II detector. The bulk of the data was collected by the SLAC Large Detector, which came online in 1991. Although largely overshadowed by the Large Electron–Positron Collider at CERN, which began running in 1989, the highly polarized electron beam at SLC (close to 80%) made certain unique measurements possible, such as parity violation in Z Boson-b quark coupling.

    Presently no beam enters the south and north arcs in the machine, which leads to the Final Focus, therefore this section is mothballed to run beam into the PEP2 section from the beam switchyard.

    The SLAC Large Detector (SLD) was the main detector for the Stanford Linear Collider. It was designed primarily to detect Z bosons produced by the accelerator’s electron-positron collisions. Built in 1991, the SLD operated from 1992 to 1998.

    PEP

    PEP (Positron-Electron Project) began operation in 1980, with center-of-mass energies up to 29 GeV. At its apex, PEP had five large particle detectors in operation, as well as a sixth smaller detector. About 300 researchers made used of PEP. PEP stopped operating in 1990, and PEP-II began construction in 1994.

    PEP-II

    From 1999 to 2008, the main purpose of the linear accelerator was to inject electrons and positrons into the PEP-II accelerator, an electron-positron collider with a pair of storage rings 2.2 km (1.4 mi) in circumference. PEP-II was host to the BaBar experiment, one of the so-called B-Factory experiments studying charge-parity symmetry.

    Fermi Gamma-ray Space Telescope

    SLAC plays a primary role in the mission and operation of the Fermi Gamma-ray Space Telescope, launched in August 2008. The principal scientific objectives of this mission are:

    To understand the mechanisms of particle acceleration in AGNs, pulsars, and SNRs.
    To resolve the gamma-ray sky: unidentified sources and diffuse emission.
    To determine the high-energy behavior of gamma-ray bursts and transients.
    To probe dark matter and fundamental physics.


    KIPAC

    The Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) is partially housed on the grounds of SLAC, in addition to its presence on the main Stanford campus.

    [/caption]

    The Stanford PULSE Institute (PULSE) is a Stanford Independent Laboratory located in the Central Laboratory at SLAC. PULSE was created by Stanford in 2005 to help Stanford faculty and SLAC scientists develop ultrafast x-ray research at LCLS.

    The Linac Coherent Light Source (LCLS)[below] is a free electron laser facility located at SLAC. The LCLS is partially a reconstruction of the last 1/3 of the original linear accelerator at SLAC, and can deliver extremely intense x-ray radiation for research in a number of areas. It achieved first lasing in April 2009.

    The laser produces hard X-rays, 10^9 times the relative brightness of traditional synchrotron sources and is the most powerful x-ray source in the world. LCLS enables a variety of new experiments and provides enhancements for existing experimental methods. Often, x-rays are used to take “snapshots” of objects at the atomic level before obliterating samples. The laser’s wavelength, ranging from 6.2 to 0.13 nm (200 to 9500 electron volts (eV)) is similar to the width of an atom, providing extremely detailed information that was previously unattainable. Additionally, the laser is capable of capturing images with a “shutter speed” measured in femtoseconds, or million-billionths of a second, necessary because the intensity of the beam is often high enough so that the sample explodes on the femtosecond timescale.

    The LCLS-II [below] project is to provide a major upgrade to LCLS by adding two new X-ray laser beams. The new system will utilize the 500 m (1,600 ft) of existing tunnel to add a new superconducting accelerator at 4 GeV and two new sets of undulators that will increase the available energy range of LCLS. The advancement from the discoveries using this new capabilities may include new drugs, next-generation computers, and new materials.

    FACET

    In 2012, the first two-thirds (~2 km) of the original SLAC LINAC were recommissioned for a new user facility, the Facility for Advanced Accelerator Experimental Tests (FACET). This facility was capable of delivering 20 GeV, 3 nC electron (and positron) beams with short bunch lengths and small spot sizes, ideal for beam-driven plasma acceleration studies. The facility ended operations in 2016 for the constructions of LCLS-II which will occupy the first third of the SLAC LINAC. The FACET-II project will re-establish electron and positron beams in the middle third of the LINAC for the continuation of beam-driven plasma acceleration studies in 2019.

    SLAC National Accelerator Laboratory(US) FACET-II upgrading its Facility for Advanced Accelerator Experimental Tests (FACET) – a test bed for new technologies that could revolutionize the way we build particle accelerators.

    The Next Linear Collider Test Accelerator (NLCTA) is a 60-120 MeV high-brightness electron beam linear accelerator used for experiments on advanced beam manipulation and acceleration techniques. It is located at SLAC’s end station B

    SSRL and LCLS are DOE Office of Science user facilities.

    Stanford University (US)

    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members.

    Stanford University, officially Leland Stanford Junior University, is a private research university located in Stanford, California. Stanford was founded in 1885 by Leland and Jane Stanford in memory of their only child, Leland Stanford Jr., who had died of typhoid fever at age 15 the previous year. Stanford is consistently ranked as among the most prestigious and top universities in the world by major education publications. It is also one of the top fundraising institutions in the country, becoming the first school to raise more than a billion dollars in a year.

    Leland Stanford was a U.S. senator and former governor of California who made his fortune as a railroad tycoon. The school admitted its first students on October 1, 1891, as a coeducational and non-denominational institution. Stanford University struggled financially after the death of Leland Stanford in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, provost Frederick Terman supported faculty and graduates’ entrepreneurialism to build self-sufficient local industry in what would later be known as Silicon Valley.

    The university is organized around seven schools: three schools consisting of 40 academic departments at the undergraduate level as well as four professional schools that focus on graduate programs in law, medicine, education, and business. All schools are on the same campus. Students compete in 36 varsity sports, and the university is one of two private institutions in the Division I FBS Pac-12 Conference. It has gained 126 NCAA team championships, and Stanford has won the NACDA Directors’ Cup for 24 consecutive years, beginning in 1994–1995. In addition, Stanford students and alumni have won 270 Olympic medals including 139 gold medals.

    As of October 2020, 84 Nobel laureates, 28 Turing Award laureates, and eight Fields Medalists have been affiliated with Stanford as students, alumni, faculty, or staff. In addition, Stanford is particularly noted for its entrepreneurship and is one of the most successful universities in attracting funding for start-ups. Stanford alumni have founded numerous companies, which combined produce more than $2.7 trillion in annual revenue, roughly equivalent to the 7th largest economy in the world (as of 2020). Stanford is the alma mater of one president of the United States (Herbert Hoover), 74 living billionaires, and 17 astronauts. It is also one of the leading producers of Fulbright Scholars, Marshall Scholars, Rhodes Scholars, and members of the United States Congress.

    Stanford University was founded in 1885 by Leland and Jane Stanford, dedicated to Leland Stanford Jr, their only child. The institution opened in 1891 on Stanford’s previous Palo Alto farm.

    Jane and Leland Stanford modeled their university after the great eastern universities, most specifically Cornell University. Stanford opened being called the “Cornell of the West” in 1891 due to faculty being former Cornell affiliates (either professors, alumni, or both) including its first president, David Starr Jordan, and second president, John Casper Branner. Both Cornell and Stanford were among the first to have higher education be accessible, nonsectarian, and open to women as well as to men. Cornell is credited as one of the first American universities to adopt this radical departure from traditional education, and Stanford became an early adopter as well.

    Despite being impacted by earthquakes in both 1906 and 1989, the campus was rebuilt each time. In 1919, The Hoover Institution on War, Revolution and Peace was started by Herbert Hoover to preserve artifacts related to World War I. The Stanford Medical Center, completed in 1959, is a teaching hospital with over 800 beds. The DOE’s SLAC National Accelerator Laboratory(US)(originally named the Stanford Linear Accelerator Center), established in 1962, performs research in particle physics.

    Land

    Most of Stanford is on an 8,180-acre (12.8 sq mi; 33.1 km^2) campus, one of the largest in the United States. It is located on the San Francisco Peninsula, in the northwest part of the Santa Clara Valley (Silicon Valley) approximately 37 miles (60 km) southeast of San Francisco and approximately 20 miles (30 km) northwest of San Jose. In 2008, 60% of this land remained undeveloped.

    Stanford’s main campus includes a census-designated place within unincorporated Santa Clara County, although some of the university land (such as the Stanford Shopping Center and the Stanford Research Park) is within the city limits of Palo Alto. The campus also includes much land in unincorporated San Mateo County (including the SLAC National Accelerator Laboratory and the Jasper Ridge Biological Preserve), as well as in the city limits of Menlo Park (Stanford Hills neighborhood), Woodside, and Portola Valley.

    Non-central campus

    Stanford currently operates in various locations outside of its central campus.

    On the founding grant:

    Jasper Ridge Biological Preserve is a 1,200-acre (490 ha) natural reserve south of the central campus owned by the university and used by wildlife biologists for research.
    SLAC National Accelerator Laboratory is a facility west of the central campus operated by the university for the Department of Energy. It contains the longest linear particle accelerator in the world, 2 miles (3.2 km) on 426 acres (172 ha) of land.
    Golf course and a seasonal lake: The university also has its own golf course and a seasonal lake (Lake Lagunita, actually an irrigation reservoir), both home to the vulnerable California tiger salamander. As of 2012 Lake Lagunita was often dry and the university had no plans to artificially fill it.

    Off the founding grant:

    Hopkins Marine Station, in Pacific Grove, California, is a marine biology research center owned by the university since 1892.
    Study abroad locations: unlike typical study abroad programs, Stanford itself operates in several locations around the world; thus, each location has Stanford faculty-in-residence and staff in addition to students, creating a “mini-Stanford”.

    Redwood City campus for many of the university’s administrative offices located in Redwood City, California, a few miles north of the main campus. In 2005, the university purchased a small, 35-acre (14 ha) campus in Midpoint Technology Park intended for staff offices; development was delayed by The Great Recession. In 2015 the university announced a development plan and the Redwood City campus opened in March 2019.

    The Bass Center in Washington, DC provides a base, including housing, for the Stanford in Washington program for undergraduates. It includes a small art gallery open to the public.

    China: Stanford Center at Peking University, housed in the Lee Jung Sen Building, is a small center for researchers and students in collaboration with Beijing University [北京大学](CN) (Kavli Institute for Astronomy and Astrophysics at Peking University(CN) (KIAA-PKU).

    Administration and organization

    Stanford is a private, non-profit university that is administered as a corporate trust governed by a privately appointed board of trustees with a maximum membership of 38. Trustees serve five-year terms (not more than two consecutive terms) and meet five times annually.[83] A new trustee is chosen by the current trustees by ballot. The Stanford trustees also oversee the Stanford Research Park, the Stanford Shopping Center, the Cantor Center for Visual Arts, Stanford University Medical Center, and many associated medical facilities (including the Lucile Packard Children’s Hospital).

    The board appoints a president to serve as the chief executive officer of the university, to prescribe the duties of professors and course of study, to manage financial and business affairs, and to appoint nine vice presidents. The provost is the chief academic and budget officer, to whom the deans of each of the seven schools report. Persis Drell became the 13th provost in February 2017.

    As of 2018, the university was organized into seven academic schools. The schools of Humanities and Sciences (27 departments), Engineering (nine departments), and Earth, Energy & Environmental Sciences (four departments) have both graduate and undergraduate programs while the Schools of Law, Medicine, Education and Business have graduate programs only. The powers and authority of the faculty are vested in the Academic Council, which is made up of tenure and non-tenure line faculty, research faculty, senior fellows in some policy centers and institutes, the president of the university, and some other academic administrators, but most matters are handled by the Faculty Senate, made up of 55 elected representatives of the faculty.

    The Associated Students of Stanford University (ASSU) is the student government for Stanford and all registered students are members. Its elected leadership consists of the Undergraduate Senate elected by the undergraduate students, the Graduate Student Council elected by the graduate students, and the President and Vice President elected as a ticket by the entire student body.

    Stanford is the beneficiary of a special clause in the California Constitution, which explicitly exempts Stanford property from taxation so long as the property is used for educational purposes.

    Endowment and donations

    The university’s endowment, managed by the Stanford Management Company, was valued at $27.7 billion as of August 31, 2019. Payouts from the Stanford endowment covered approximately 21.8% of university expenses in the 2019 fiscal year. In the 2018 NACUBO-TIAA survey of colleges and universities in the United States and Canada, only Harvard University(US), the University of Texas System(US), and Yale University(US) had larger endowments than Stanford.

    In 2006, President John L. Hennessy launched a five-year campaign called the Stanford Challenge, which reached its $4.3 billion fundraising goal in 2009, two years ahead of time, but continued fundraising for the duration of the campaign. It concluded on December 31, 2011, having raised a total of $6.23 billion and breaking the previous campaign fundraising record of $3.88 billion held by Yale. Specifically, the campaign raised $253.7 million for undergraduate financial aid, as well as $2.33 billion for its initiative in “Seeking Solutions” to global problems, $1.61 billion for “Educating Leaders” by improving K-12 education, and $2.11 billion for “Foundation of Excellence” aimed at providing academic support for Stanford students and faculty. Funds supported 366 new fellowships for graduate students, 139 new endowed chairs for faculty, and 38 new or renovated buildings. The new funding also enabled the construction of a facility for stem cell research; a new campus for the business school; an expansion of the law school; a new Engineering Quad; a new art and art history building; an on-campus concert hall; a new art museum; and a planned expansion of the medical school, among other things. In 2012, the university raised $1.035 billion, becoming the first school to raise more than a billion dollars in a year.

    Research centers and institutes

    DOE’s SLAC National Accelerator Laboratory(US)
    Stanford Research Institute, a center of innovation to support economic development in the region.
    Hoover Institution, a conservative American public policy institution and research institution that promotes personal and economic liberty, free enterprise, and limited government.
    Hasso Plattner Institute of Design, a multidisciplinary design school in cooperation with the Hasso Plattner Institute of University of Potsdam [Universität Potsdam](DE) that integrates product design, engineering, and business management education).
    Martin Luther King Jr. Research and Education Institute, which grew out of and still contains the Martin Luther King Jr. Papers Project.
    John S. Knight Fellowship for Professional Journalists
    Center for Ocean Solutions
    Together with UC Berkeley(US) and UC San Francisco(US), Stanford is part of the Biohub, a new medical science research center founded in 2016 by a $600 million commitment from Facebook CEO and founder Mark Zuckerberg and pediatrician Priscilla Chan.

    Discoveries and innovation

    Natural sciences

    Biological synthesis of deoxyribonucleic acid (DNA) – Arthur Kornberg synthesized DNA material and won the Nobel Prize in Physiology or Medicine 1959 for his work at Stanford.
    First Transgenic organism – Stanley Cohen and Herbert Boyer were the first scientists to transplant genes from one living organism to another, a fundamental discovery for genetic engineering. Thousands of products have been developed on the basis of their work, including human growth hormone and hepatitis B vaccine.
    Laser – Arthur Leonard Schawlow shared the 1981 Nobel Prize in Physics with Nicolaas Bloembergen and Kai Siegbahn for his work on lasers.
    Nuclear magnetic resonance – Felix Bloch developed new methods for nuclear magnetic precision measurements, which are the underlying principles of the MRI.

    Computer and applied sciences

    ARPANETStanford Research Institute, formerly part of Stanford but on a separate campus, was the site of one of the four original ARPANET nodes.

    Internet—Stanford was the site where the original design of the Internet was undertaken. Vint Cerf led a research group to elaborate the design of the Transmission Control Protocol (TCP/IP) that he originally co-created with Robert E. Kahn (Bob Kahn) in 1973 and which formed the basis for the architecture of the Internet.

    Frequency modulation synthesis – John Chowning of the Music department invented the FM music synthesis algorithm in 1967, and Stanford later licensed it to Yamaha Corporation.

    Google – Google began in January 1996 as a research project by Larry Page and Sergey Brin when they were both PhD students at Stanford. They were working on the Stanford Digital Library Project (SDLP). The SDLP’s goal was “to develop the enabling technologies for a single, integrated and universal digital library” and it was funded through the National Science Foundation, among other federal agencies.

    Klystron tube – invented by the brothers Russell and Sigurd Varian at Stanford. Their prototype was completed and demonstrated successfully on August 30, 1937. Upon publication in 1939, news of the klystron immediately influenced the work of U.S. and UK researchers working on radar equipment.

    RISCARPA funded VLSI project of microprocessor design. Stanford and UC Berkeley are most associated with the popularization of this concept. The Stanford MIPS would go on to be commercialized as the successful MIPS architecture, while Berkeley RISC gave its name to the entire concept, commercialized as the SPARC. Another success from this era were IBM’s efforts that eventually led to the IBM POWER instruction set architecture, PowerPC, and Power ISA. As these projects matured, a wide variety of similar designs flourished in the late 1980s and especially the early 1990s, representing a major force in the Unix workstation market as well as embedded processors in laser printers, routers and similar products.
    SUN workstation – Andy Bechtolsheim designed the SUN workstation for the Stanford University Network communications project as a personal CAD workstation, which led to Sun Microsystems.

    Businesses and entrepreneurship

    Stanford is one of the most successful universities in creating companies and licensing its inventions to existing companies; it is often held up as a model for technology transfer. Stanford’s Office of Technology Licensing is responsible for commercializing university research, intellectual property, and university-developed projects.

    The university is described as having a strong venture culture in which students are encouraged, and often funded, to launch their own companies.

    Companies founded by Stanford alumni generate more than $2.7 trillion in annual revenue, equivalent to the 10th-largest economy in the world.

    Some companies closely associated with Stanford and their connections include:

    Hewlett-Packard, 1939, co-founders William R. Hewlett (B.S, PhD) and David Packard (M.S).
    Silicon Graphics, 1981, co-founders James H. Clark (Associate Professor) and several of his grad students.
    Sun Microsystems, 1982, co-founders Vinod Khosla (M.B.A), Andy Bechtolsheim (PhD) and Scott McNealy (M.B.A).
    Cisco, 1984, founders Leonard Bosack (M.S) and Sandy Lerner (M.S) who were in charge of Stanford Computer Science and Graduate School of Business computer operations groups respectively when the hardware was developed.[163]
    Yahoo!, 1994, co-founders Jerry Yang (B.S, M.S) and David Filo (M.S).
    Google, 1998, co-founders Larry Page (M.S) and Sergey Brin (M.S).
    LinkedIn, 2002, co-founders Reid Hoffman (B.S), Konstantin Guericke (B.S, M.S), Eric Lee (B.S), and Alan Liu (B.S).
    Instagram, 2010, co-founders Kevin Systrom (B.S) and Mike Krieger (B.S).
    Snapchat, 2011, co-founders Evan Spiegel and Bobby Murphy (B.S).
    Coursera, 2012, co-founders Andrew Ng (Associate Professor) and Daphne Koller (Professor, PhD).

    Student body

    Stanford enrolled 6,996 undergraduate and 10,253 graduate students as of the 2019–2020 school year. Women comprised 50.4% of undergraduates and 41.5% of graduate students. In the same academic year, the freshman retention rate was 99%.

    Stanford awarded 1,819 undergraduate degrees, 2,393 master’s degrees, 770 doctoral degrees, and 3270 professional degrees in the 2018–2019 school year. The four-year graduation rate for the class of 2017 cohort was 72.9%, and the six-year rate was 94.4%. The relatively low four-year graduation rate is a function of the university’s coterminal degree (or “coterm”) program, which allows students to earn a master’s degree as a 1-to-2-year extension of their undergraduate program.

    As of 2010, fifteen percent of undergraduates were first-generation students.

    Athletics

    As of 2016 Stanford had 16 male varsity sports and 20 female varsity sports, 19 club sports and about 27 intramural sports. In 1930, following a unanimous vote by the Executive Committee for the Associated Students, the athletic department adopted the mascot “Indian.” The Indian symbol and name were dropped by President Richard Lyman in 1972, after objections from Native American students and a vote by the student senate. The sports teams are now officially referred to as the “Stanford Cardinal,” referring to the deep red color, not the cardinal bird. Stanford is a member of the Pac-12 Conference in most sports, the Mountain Pacific Sports Federation in several other sports, and the America East Conference in field hockey with the participation in the inter-collegiate NCAA’s Division I FBS.

    Its traditional sports rival is the University of California, Berkeley, the neighbor to the north in the East Bay. The winner of the annual “Big Game” between the Cal and Cardinal football teams gains custody of the Stanford Axe.

    Stanford has had at least one NCAA team champion every year since the 1976–77 school year and has earned 126 NCAA national team titles since its establishment, the most among universities, and Stanford has won 522 individual national championships, the most by any university. Stanford has won the award for the top-ranked Division 1 athletic program—the NACDA Directors’ Cup, formerly known as the Sears Cup—annually for the past twenty-four straight years. Stanford athletes have won medals in every Olympic Games since 1912, winning 270 Olympic medals total, 139 of them gold. In the 2008 Summer Olympics, and 2016 Summer Olympics, Stanford won more Olympic medals than any other university in the United States. Stanford athletes won 16 medals at the 2012 Summer Olympics (12 gold, two silver and two bronze), and 27 medals at the 2016 Summer Olympics.

    Traditions

    The unofficial motto of Stanford, selected by President Jordan, is Die Luft der Freiheit weht. Translated from the German language, this quotation from Ulrich von Hutten means, “The wind of freedom blows.” The motto was controversial during World War I, when anything in German was suspect; at that time the university disavowed that this motto was official.
    Hail, Stanford, Hail! is the Stanford Hymn sometimes sung at ceremonies or adapted by the various University singing groups. It was written in 1892 by mechanical engineering professor Albert W. Smith and his wife, Mary Roberts Smith (in 1896 she earned the first Stanford doctorate in Economics and later became associate professor of Sociology), but was not officially adopted until after a performance on campus in March 1902 by the Mormon Tabernacle Choir.
    “Uncommon Man/Uncommon Woman”: Stanford does not award honorary degrees, but in 1953 the degree of “Uncommon Man/Uncommon Woman” was created to recognize individuals who give rare and extraordinary service to the University. Technically, this degree is awarded by the Stanford Associates, a voluntary group that is part of the university’s alumni association. As Stanford’s highest honor, it is not conferred at prescribed intervals, but only when appropriate to recognize extraordinary service. Recipients include Herbert Hoover, Bill Hewlett, Dave Packard, Lucile Packard, and John Gardner.
    Big Game events: The events in the week leading up to the Big Game vs. UC Berkeley, including Gaieties (a musical written, composed, produced, and performed by the students of Ram’s Head Theatrical Society).
    “Viennese Ball”: a formal ball with waltzes that was initially started in the 1970s by students returning from the now-closed Stanford in Vienna overseas program. It is now open to all students.
    “Full Moon on the Quad”: An annual event at Main Quad, where students gather to kiss one another starting at midnight. Typically organized by the Junior class cabinet, the festivities include live entertainment, such as music and dance performances.
    “Band Run”: An annual festivity at the beginning of the school year, where the band picks up freshmen from dorms across campus while stopping to perform at each location, culminating in a finale performance at Main Quad.
    “Mausoleum Party”: An annual Halloween Party at the Stanford Mausoleum, the final resting place of Leland Stanford Jr. and his parents. A 20-year tradition, the “Mausoleum Party” was on hiatus from 2002 to 2005 due to a lack of funding, but was revived in 2006. In 2008, it was hosted in Old Union rather than at the actual Mausoleum, because rain prohibited generators from being rented. In 2009, after fundraising efforts by the Junior Class Presidents and the ASSU Executive, the event was able to return to the Mausoleum despite facing budget cuts earlier in the year.
    Former campus traditions include the “Big Game bonfire” on Lake Lagunita (a seasonal lake usually dry in the fall), which was formally ended in 1997 because of the presence of endangered salamanders in the lake bed.

    Award laureates and scholars

    Stanford’s current community of scholars includes:

    19 Nobel Prize laureates (as of October 2020, 85 affiliates in total)
    171 members of the National Academy of Sciences
    109 members of National Academy of Engineering
    76 members of National Academy of Medicine
    288 members of the American Academy of Arts and Sciences
    19 recipients of the National Medal of Science
    1 recipient of the National Medal of Technology
    4 recipients of the National Humanities Medal
    49 members of American Philosophical Society
    56 fellows of the American Physics Society (since 1995)
    4 Pulitzer Prize winners
    31 MacArthur Fellows
    4 Wolf Foundation Prize winners
    2 ACL Lifetime Achievement Award winners
    14 AAAI fellows
    2 Presidential Medal of Freedom winners

    Stanford University Seal

     
  • richardmitnick 10:28 am on February 25, 2021 Permalink | Reply
    Tags: "The Joy of Condensed Matter", A “magnon” is a quasiparticle of magnetization., A “phonon” is a quasiparticle of sound formed from vibrations moving through a crystal., An exciton is a bound state of an electron and an electron hole which are attracted to each other by the electrostatic Coulomb force., , As of now research in fundamental physics has given us the Standard Model and General Relativity (which describes gravity)., , Big questions remain unanswered—like the nature of Dark Matter or whatever is fooling us into thinking there’s dark matter., Condensed Matter Physics, Everyone seems to be talking about the problems with physics., Hard times in fundamental physics got you down? Let’s talk excitons., , Physicists have a name for things that act like particles even though they’re not: “quasiparticles.”, , The idea of excitons goes back all the way to 1931., Traditionally the job of condensed matter physics was to predict the properties of solids and liquids found in nature.   

    From Nautilus: “The Joy of Condensed Matter” 

    From Nautilus

    February 24, 2021
    John C. Baez

    Hard times in fundamental physics got you down? Let’s talk excitons.

    Everyone seems to be talking about the problems with physics: Peter Woit’s book Not Even Wrong, Lee Smolin’s The Trouble With Physics, and Sabine Hossenfelder’s Lost in Math leap to mind, and they have started a wider conversation. But is all of physics really in trouble, or just some of it? If you actually read these books, you’ll see they’re about so-called “fundamental” physics. Some other parts of physics are doing just fine, and I want to tell you about one. It’s called “condensed matter physics,” and it’s the study of solids and liquids. We are living in the golden age of condensed matter physics.

    But first, what is “fundamental” physics? It’s a tricky term. You might think any truly revolutionary development in physics counts as fundamental. But in fact physicists use this term in a more precise, narrowly delimited way. One of the goals of physics is to figure out some laws that, at least in principle, we could use to predict everything that can be predicted about the physical universe. The search for these laws is fundamental physics.

    The fine print is crucial. First: “in principle.” In principle we can use the fundamental physics we know to calculate the boiling point of water to immense accuracy—but nobody has done it yet, because the calculation is hard. Second: “everything that can be predicted.” As far we can tell, quantum mechanics says there’s inherent randomness in things, which makes some predictions impossible, not just impractical, to carry out with certainty. And this inherent quantum randomness sometimes gets amplified over time, by a phenomenon called chaos. For this reason, even if we knew everything about the universe now, we couldn’t predict the weather precisely a year from now. So, even if fundamental physics succeeded perfectly, it would be far from giving the answer to all our questions about the physical world. But it’s important nonetheless, because it gives us the basic framework in which we can try to answer these questions.

    As of now research in fundamental physics has given us the Standard Model (which seeks to describe matter and all the forces except gravity) and General Relativity (which describes gravity).

    Standard Model of Particle Physics (LATHAM BOYLE AND MARDUS OF WIKIMEDIA COMMONS).

    These theories are tremendously successful, but we know they are not the last word. Big questions remain unanswered—like the nature of Dark Matter or whatever is fooling us into thinking there’s dark matter. Unfortunately, progress on these questions has been very slow since the 1990s. Luckily fundamental physics is not all of physics, and today it is no longer the most exciting part of physics. There is still plenty of mind-blowing new physics being done. And a lot of it—though by no means all—is condensed matter physics.

    Traditionally the job of condensed matter physics was to predict the properties of solids and liquids found in nature. Sometimes this can be very hard: for example, computing the boiling point of water. But now we know enough fundamental physics to design strange new materials—and then actually make these materials, and probe their properties with experiments, testing our theories of how they should work. Even better, these experiments can often be done on a table top. There’s no need for enormous particle accelerators here.

    Let’s look at an example. We’ll start with the humble “hole.” A crystal is a regular array of atoms, each with some electrons orbiting it. When one of these electrons gets knocked off somehow, we get a “hole”: an atom with a missing electron. And this hole can actually move around like a particle! When an electron from some neighboring atom moves to fill the hole, the hole moves to the neighboring atom. Imagine a line of people all wearing hats except for one whose head is bare: If their neighbor lends them their hat, the bare head moves to the neighbor. If this keeps happening, the bare head will move down the line of people. The absence of a thing can act like a thing!

    The famous physicist Paul Dirac came up with the idea of holes in 1930. He correctly predicted that since electrons have negative electric charge, holes should have positive charge. Dirac was working on fundamental physics: He hoped the proton could be explained as a hole. That turned out not to be true. Later physicists found another particle that could: the “positron.” It’s just like an electron with the opposite charge. And thus antimatter—the evil twin of ordinary matter, with the same mass but the opposite charge—was born. (But that’s another story.)

    In 1931, Werner Heisenberg applied the idea of holes to condensed matter physics. He realized that, just as electrons create an electrical current as they move along, so do holes—but because they’re positively charged, their electrical current goes in the other direction! It became clear that holes carry electrical current in some of the materials called “semiconductors”: for example, silicon with a bit of aluminum added to it. After many further developments, in 1948 the physicist William Schockley patented transistors that use both holes and electrons to form a kind of switch. He later won the Nobel Prize for this, and now they’re widely used in computer chips.

    Holes in semiconductors are not really particles in the sense of fundamental physics. They are just a convenient way of thinking about the motion of electrons. But any sufficiently convenient abstraction takes on a life of its own. The equations that describe the behavior of holes are just like the equations that describe the behavior of particles. So, we can treat holes as if they are particles. We’ve already seen that a hole is positively charged. But because it takes energy to get a hole moving, a hole also acts like it has a mass. And so on: The properties we normally attribute to particles also make sense for holes.

    Physicists have a name for things that act like particles even though they’re not: “quasiparticles.” There are many kinds; holes are just one of the simplest. The beauty of quasiparticles is that we can practically make them to order, having a vast variety of properties. As the quantum physicist Michael Nielsen put it, we now live in the era of “designer matter.”

    For example, consider the “exciton.” Since an electron is negatively charged and a hole is positively charged, they attract each other. And if the hole is much heavier than the electron—remember, a hole has a mass—an electron can orbit a hole much as an electron orbits a proton in a hydrogen atom. Thus, they form a kind of artificial atom called an exciton. It’s a ghostly dance of presence and absence!

    1
    OPPOSITES ATTRACT: This is how an exciton, the binding together of a positively charged “hole” and an electron, moves inside a crystal lattice. Credit: Wikipedia.

    The idea of excitons goes back all the way to 1931. By now we can make excitons in large quantities in certain semiconductors and other materials. They don’t last for long: The electron quickly falls back into the hole. It often takes less than a billionth of a second for this to happen. But that’s enough time to do some interesting things. Just as two atoms of hydrogen can stick together and form a molecule, two excitons can stick together and form a “biexciton.” An exciton can stick to another hole and form a “trion.” An exciton can even stick to a photon—a particle of light—and form something called a “polariton.” It’s a blend of matter and light!

    Can you make a gas of artificial atoms? Yes! At low densities and high temperatures, excitons zip around very much like atoms in a gas. Can you make a liquid? Again, yes: At higher densities, and colder temperatures, excitons bump into each other enough to act like a liquid. At even colder temperatures, excitons can even form a “superfluid,” with almost zero viscosity: if you could somehow get it swirling around, it would go on practically forever.

    This is just a small taste of what researchers in condensed matter physics are doing these days. Besides excitons, they are studying a host of other quasiparticles. A “phonon” is a quasiparticle of sound formed from vibrations moving through a crystal. A “magnon” is a quasiparticle of magnetization: a pulse of electrons in a crystal whose spins have flipped. The list goes on, and becomes ever more esoteric.

    But there is also much more to the field than quasiparticles. Physicists can now create materials in which the speed of light is much slower than usual, say 40 miles an hour. They can even create materials in which light moves as if there were two space dimensions and two time dimensions, instead of the usual three dimensions of space and one of time! Normally we think that time can go forward in just one direction, but in these substances light has a choice between many different directions it can go “forward in time.” On the other hand, its motion in space is confined to a plane.

    In short, the possibilities of condensed matter are limited only by our imagination and the fundamental laws of physics.

    At this point, usually some skeptic comes along and questions whether these things are useful. Indeed, some of these new materials are likely to be useful. In fact a lot of condensed matter physics, while less glamorous than what I have just described, is carried out precisely to develop new improved computer chips—and also technologies like “photonics,” which uses light instead of electrons. The fruits of photonics are ubiquitous—it saturates modern technology, like flat-screen TVs—but physicists are now aiming for more radical applications, like computers that process information using light.

    Then typically some other kind of skeptic comes along and asks if condensed matter physics is “just engineering.” Of course the very premise of this question is insulting: There is nothing wrong with engineering! Trying to build useful things is not only important in itself, it’s a great way to raise deep new questions about physics. For example, the whole field of thermodynamics, and the idea of entropy, arose in part from trying to build better steam engines. But condensed matter physics is not just engineering. Large portions of it are blue-sky research into the possibilities of matter, like I’ve been talking about here.

    These days, the field of condensed matter physics is just as full of rewarding new insights as the study of elementary particles or black holes. And unlike fundamental physics, progress in condensed matter physics is rapid—in part because experiments are comparatively cheap and easy, and in part because there is more new territory to explore.

    So, when you see someone bemoaning the woes of fundamental physics, take them seriously—but don’t let it get you down. Just find a good article on condensed matter physics and read that. You’ll cheer up immediately.

    See the full article here .

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    Welcome to Nautilus. We are delighted you joined us. We are here to tell you about science and its endless connections to our lives. Each month we choose a single topic. And each Thursday we publish a new chapter on that topic online. Each issue combines the sciences, culture and philosophy into a single story told by the world’s leading thinkers and writers. We follow the story wherever it leads us. Read our essays, investigative reports, and blogs. Fiction, too. Take in our games, videos, and graphic stories. Stop in for a minute, or an hour. Nautilus lets science spill over its usual borders. We are science, connected.

     
  • richardmitnick 2:22 pm on February 22, 2021 Permalink | Reply
    Tags: , Condensed Matter Physics, , One of the biggest unsolved problems in condensed-matter physics is explaining the origin of high-temperature superconductivity., , , QGM-Quantum gas microscope, QGMs are used to image arrays of fermions., Researchers have developed an ion-optics-based quantum microscope that has sufficient resolution to image individual atoms., The team designed an ion-optics-based system.   

    From Physics: “Ion Microscopy Goes Quantum” 

    About Physics

    From Physics

    February 22, 2021
    Arturo Camacho-Guardian

    Researchers have developed an ion-optics-based quantum microscope that has sufficient resolution to image individual atoms.

    1
    Figure 1: Researchers demonstrate an ion-optics-based microscope that can resolve individual charged atoms. The atoms are confined in a one-dimensional optical lattice (bottom of image) and then illuminated with a light pulse, which ionizes the atoms (green balls). After a short delay, the ionized atoms are transferred into the ion-optic system, where they are manipulated with electrostatic lenses (red rectangles) and imaged with an ion detector (top of image). The arrow indicates the direction of travel of the ions through the microscope. Credit: Alan Stonebraker/APS.

    One of the biggest unsolved problems in condensed-matter physics is explaining the origin of high-temperature superconductivity, a phenomenon where materials conduct electricity with zero resistance at temperatures well above those predicted by theory. Researchers think that the behavior is made possible by strong interactions among a material’s constituents. But, because of the complexity of these systems, numerical calculations of their behaviors are unfeasible, making it hard to confirm this—or any other—theoretical idea. Experiments offer opportunities for tackling the problem, particularly those involving ultracold atomic gases (see Coming Soon: Cold Atoms Impersonate Superconductors). Now a team lead by Tilman Pfau at the University of Stuttgart [Universität Stuttgart](DE), has reported a new tool for researchers studying ultracold gases: a quantum microscope based on ion optics that can resolve individual charged atoms [1]. The technology could provide a means to uncover new insights into strongly interacting materials.

    For any microscope to be useful, it must have a resolving power sufficient to image the features of interest. For quantum gases, these features, which include atoms and their spatial order, typically have submicrometer length scales. Such small features are hard to image with traditional-optics-based quantum microscopes, whose highest resolution is 5μm.

    This resolution problem was partially solved in 2009 with the arrival of the first quantum gas microscope (QGM), which can capture features down to 0.5μm in size [2]. The device allows researchers to arrange atoms in a lattice pattern and then image the atoms using the fluorescent light they emit.

    QGMs are used to image arrays of fermions (in this case, atoms with an odd number of neutrons) to uncover behaviors that mimic those of electrons in solid materials. Although QGMs haven’t elucidated the high-temperature-superconducting mechanism yet, researchers are hopeful that will happen soon. But the QGM has an important limitation: It cannot image electronically excited atoms, such as Rydberg atoms, which can form exotic phases, including quantum crystals.

    The problem lies with the microscope’s use of fluorescent light. Fluorescence imaging relies on a closed-cycle transition, where an atom absorbs light, moving from one state to another, and then spontaneously emits light and decays back to its initial state. These closed cycles exist for ground-state atoms, such as the fermions imaged with QGM, but they can’t always be found for excited atoms. To image excited atoms, researchers need to leverage other phenomena, which is what Pfau and his colleagues have done.

    The team designed an ion-optics-based system. Their microscope consists of three electrostatic lenses and an ion detector that can count single ions (Fig. 1). Electrostatic lenses work using the same principles as other lenses, such as those in cameras and telescopes, which focus light using transparent curved surfaces made of glass or plastic. But, rather than manipulating light with an object, electrostatic lenses manipulate the paths of ions using electric fields. The two sets of lenses also have another key difference: The magnification of a given traditional lens is fixed, while that of an electrostatic lens is adjustable. This adjustment is made by changing the voltage of the electric fields used to create the lens, something Pfau and his colleagues leveraged in their experiments.

    In the microscope, an ultracold gas of neutral atoms is first confined in a one-dimensional lattice, as in a QGM. (Pfau and colleagues used rubidium atoms for their demonstration.) The atoms are then illuminated with a series of laser pulses. Each pulse charges between 10 and 100 atoms in a process known as photoionization. The resulting ions remain in their lattice for between 30 ns and 4μs, enough time for them to interact and build up the many-body correlations that researchers are interested in. The ions are then released into the ion microscope where they are imaged.

    The images collected by the team show that their microscope can capture features from 6.79μm down to 0.52μm in size, sufficient to image individual atoms. This maximum resolution is more than 5 times better than that achieved in 2017 with a different ion-optics-based microscope, which had a resolution of 2.7μm [3]. The new microscope also has a depth of field of 70μm. This depth is an order of magnitude larger than that of a QGM, which has a depth of field of only a few micrometers and is a big enough distance to potentially use the microscope to capture 3D images.

    This increased resolution could allow the new microscope to explore previously uncharted territory for excited atoms. For example, the microscope could be used as a tool for monitoring the so-called dressing of an impurity by its environment, a process that modifies the impurity’s properties, such as energy, charge, and mass. Dressed impurities embedded in a strongly interacting bath are predicted to play a crucial role in the behavior of high-temperature superconductors.

    Ion-optics-based microscopy also raises the possibility of unveiling the interplay between few-body correlations and macroscopic phases of matter [4, 5]. If the microscope can achieve a high-time resolution, it could help reveal the crossover between short-time dynamics, where the system is governed by two-body collisions, and long-time dynamics, where many-body correlations can lead to the formation of intriguing new quantum states. So far, this crossover has only been observed for ground-state atoms [6, 7].

    Finally, the single-site resolution achieved by Pfau and colleagues could allow for the study of few- and many-body effects, such as crystallization, in gases containing Rydberg atoms [8] as well as in quantum phases prepared from ground-state atoms. These studies could provide a deeper understanding of the most complex strongly correlated systems in atomic and condensed-matter physics.

    References

    1.C. Veit et al., “Pulsed ion microscope to probe quantum gases,” Phys. Rev. X 11, 011036 (2021).
    2.W. S. Bakr et al., “A quantum gas microscope for detecting single atoms in a Hubbard-regime optical lattice,” Nature 462, 74 (2009).
    3.M. Stecker et al., “A high resolution ion microscope for cold atoms,” New J. Phys. 19, 043020 (2017).
    4. G. E. Astrakharchik et al., “Ionic polaron in a Bose-Einstein condensate,” arXiv:2005.12033.
    5. R. Christensen et al., “Charged polarons and molecules in a Bose-Einstein condensate,” arXiv:2012.11436.
    6.M. Cetina et al., “Ultrafast many-body interferometry of impurities coupled to a Fermi sea,” Science 354, 96 (2016).
    7.M. Skou et al., “Non-equilibrium dynamics of quantum impurities,” arXiv:2005.00424.
    8.P. Schauss et al., “Crystallization in Ising quantum magnets,” Science 347, 1455 (2015).

    See the full article here .

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    Please help promote STEM in your local schools.

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    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments.

     
  • richardmitnick 12:31 pm on February 15, 2021 Permalink | Reply
    Tags: "Speeding Up Ultrafast Spectroscopy", , Code packages and demonstrations are notably available for Matlab [5] and Python [9]., Condensed Matter Physics, CS involves reconstructing a signal from a randomly (and drastically) downsampled dataset., CS-"Compressive sensing", , Thousands of time-consuming individual measurements must usually be made., Ultrafast spectroscopy would be an ideal characterization technique for many scientific and industrial applications if only it weren’t so slow.   

    From “Physics”: “Speeding Up Ultrafast Spectroscopy” 

    About Physics

    From “Physics”

    February 15, 2021
    Rachel Ostic
    Jean-Michel Ménard

    A signal-processing algorithm called “compressive sensing” lets researchers characterize a sample with ultrafast spectroscopy using far fewer measurements than before.

    1
    Figure 1: Schematic application of compressive sensing to THz time-domain spectroscopy. (Top left) A terahertz pulse is incident on a sample. (Top right) The pulse is shown after traveling through the sample with a trailing oscillatory tail indicating the presence of molecular resonances. (Bottom) The resulting signal is composed of three different peaks, giving a sparse frequency-domain representation.
    Credit: J.-M. Ménard/University of Ottawa; adapted by APS/Alan Stonebraker.

    Ultrafast spectroscopy would be an ideal characterization technique for many scientific and industrial applications if only it weren’t so slow. To accurately characterize a given sample, thousands of time-consuming individual measurements must usually be made, adding up to a process that can take minutes or even hours. But what if we could forgo most of these measurements without compromising the technique’s reliability? This solution may seem too good to be true, but it is one that has now been demonstrated by Sushovit Adhikari at the Argonne National Laboratory, Illinois, and colleagues. The team applied an algorithmic approach called compressive sensing (CS) to two ultrafast spectroscopy techniques, reducing their measurement time by a factor of 6 [1]. This improvement may make a new range of condensed-matter experiments more broadly accessible. It could also bring cutting-edge optical technologies closer to industrial applications, especially in the field of product quality control.

    Spectroscopic characterization techniques possess an intrinsic trade-off between data-acquisition speed and measurement sensitivity. Repeating measurements reduces experimental noise and increases accuracy through an averaging process, but more time is then required to collect a full dataset. There are two complementary approaches to address this challenge: a “hardware” approach, which focuses on improving the experimental equipment by, for example, increasing detector sensitivity, boosting signal emission, or reducing environmental noise; and a “software” approach, in which data acquisition is accelerated by means of signal-processing tools. As a mathematical algorithm for fitting and reconstructing experimental data, CS falls into this latter category. Developed in the 1990s and 2000s [2–4], the approach is often associated with the fields of nuclear magnetic resonance (NMR) and spatial imaging, where it was first deployed [4–7]. But the concept can be applied to virtually any experimental signal.

    CS involves reconstructing a signal from a randomly (and drastically) downsampled dataset. In comparison to standard methods of data collection, therefore, CS saves lab time by allowing experimentalists to rely on fewer sampled data points while achieving the same resolution. It is not quite a free lunch though—the measured signal must obey an important condition: that it is sparse when transformed into another known basis. For instance, a signal that at first appears complex might, when transformed into another basis, turn out to be dominated by just a small number of select frequencies (Fig. 1). Such a signal is sparse in the frequency domain and can be efficiently analyzed with CS. This condition may seem restrictive, but it is fulfilled by many signals.

    As Adhikari and colleagues show, the ability of CS to make do with fewer data points makes the technique particularly well suited to multidimensional measurements. Obtaining such measurements using a conventional signal-processing method would usually involve scanning over the full parameter space in every variable. By downsampling this parameter space for each variable, CS allows these measurements to be made with significant data-acquisition-rate benefits [1, 4–8]. This efficiency improvement has the added advantage that samples are less prone to degradation from long exposure to the probe. In the case of characterization techniques that use beams of electrons or ionizing photons, some materials cannot withstand the high dose associated with a long averaging time [6]. CS thereby helps to overcome limitations related to both sample throughput and measurement stability.

    Adhikari and colleagues demonstrate this advantage by using CS to reduce, by a factor of 6, the data acquisition for two optical pump-probe experiments: ultrafast transient absorption spectroscopy and ultrafast terahertz (THz) spectroscopy [1]. In both experiments, data acquisition takes place over two dimensions. In other words, data are collected while varying two independent experimental parameters such as the time interval between optical pulses and the optical wavelength. The team’s first step is to randomly downsample this measurement space. They do this at different sampling fractions to verify the integrity of the reconstruction for various amounts of data. They also present a strategy to validate the reconstruction process as more data are added. This validation would be achieved by repeating the CS reconstruction for each new data point until the error between consecutive reconstructions falls below a certain threshold.

    Experimentalists looking to replicate the team’s approach with other characterization techniques will be glad to know that they do not have to start from scratch. Code packages and demonstrations are notably available for Matlab [5] and Python [9], with the small caveat that they will need to be adapted to each type of measurement by integrating the numerical tools into the instrumental automation aspect, selecting a correct sparse basis transformation, and defining appropriate stopping criteria.

    After the success of CS in applications such as NMR [5], single-pixel imaging [4], and quantum chemistry [8], we expect this new demonstration to raise the technique’s profile within the broad ultrafast-spectroscopy community. Longer term, machine learning and CS could be combined synergistically [7] to automate the process of deducing the ideal transformation that delivers the necessary sparse bases for the CS algorithm.

    Despite the potential of CS to improve the efficiency of ultrafast spectroscopy, researchers should bear in mind a significant limitation: CS may not perform well if the signal is not actually sparse. Nevertheless, we imagine that this technique could be a natural match to spectroscopy applications that seek to investigate and quantify spectral resonances in materials. We expect that “software-like” advances will gain ground, especially in industry, where they may be crucial to the implementation of ultrafast techniques for product characterization.

    References

    S. Adhikari et al., “Accelerating ultrafast spectroscopy with compressive sensing,” Phys. Rev. Applied 15, 024032 (2021).
    D. L. Donoho, “Compressed sensing,” IEEE Trans. Inf. Theory 52, 1289 (2006).
    E. J. Candes and M. B. Wakin, “An introduction to compressive sampling,” IEEE Signal Process. Mag. 25, 21 (2008).
    G. M. Gibson et al., “Single-pixel imaging 12 years on: A review,” Opt. Express 28, 28190 (2020).
    A. Shchukina et al., “Pitfalls in compressed sensing reconstruction and how to avoid them,” J Biomol. NMR 68, 79 (2016).
    L. Kovarik et al., “Implementing an accurate and rapid sparse sampling approach for low-dose atomic resolution STEM imaging,” Appl. Phys. Lett. 109, 164102 (2016).
    A. Bustin et al., “From compressed-sensing to artificial intelligence-based cardiac MRI reconstruction,” Front. Cardiovasc. Med. 7, 17 (2020).
    J. N. Sanders et al., “Compressed sensing for multidimensional spectroscopy experiments,” J. Phys. Chem. Lett. 3, 2697 (2012).
    M. Kliesch, “pit—Pictures: Iterative Thresholding algorithms,” GitHub repository, https://github.com/MartKl/CS_image_recovery_demo (2020).

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Physicists are drowning in a flood of research papers in their own fields and coping with an even larger deluge in other areas of physics. How can an active researcher stay informed about the most important developments in physics? Physics highlights a selection of papers from the Physical Review journals. In consultation with expert scientists, the editors choose these papers for their importance and/or intrinsic interest. To highlight these papers, Physics features three kinds of articles: Viewpoints are commentaries written by active researchers, who are asked to explain the results to physicists in other subfields. Focus stories are written by professional science writers in a journalistic style and are intended to be accessible to students and non-experts. Synopses are brief editor-written summaries. Physics provides a much-needed guide to the best in physics, and we welcome your comments (physics@aps.org).

     
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