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  • richardmitnick 11:46 am on September 26, 2021 Permalink | Reply
    Tags: "One of nature’s key constants is much larger in a quantum material", , "Spinons", , If the fine-structure constant throughout the cosmos were as large as the one in quantum spin ices “the periodic table would only have 10 elements., , Quantum Physics, Quantum spin ices are a class of substances in which particles can’t agree., , The fine-structure constant is about 10 times its normal value in a type of material called quantum spin ice., The impasse occurs because of the materials’ geometry: The particles are located at the corners of an array of pyramids that are connected at the corners., Unfortunately scientists haven’t yet found a material that definitively qualifies as quantum spin ice.   

    From “Science News (US) : “One of nature’s key constants is much larger in a quantum material” 

    From “Science News (US)

    September 21, 2021
    Emily Conover

    1
    Particles with the quantum property called spin, illustrated by the blue arrow, can’t agree on an orientation in a type of material called quantum spin ice. Credit: ELLA MARU STUDIO/Science Source.

    The fine-structure constant is about 10 times its normal value in a type of material called quantum spin ice, physicists calculate in the Sept. 10 Physical Review Letters. The new calculation hints that quantum spin ice could give a glimpse at physics within an alternate universe where the constant is much larger.

    With an influence that permeates physics and chemistry, the fine-structure constant sets the strength of interactions between electrically charged particles. Its value, about 1/137, consternates physicists because they can’t explain why it has that value, even though it is necessary for the complex chemistry that is the basis of life (SN: 11/2/16).

    If the fine-structure constant throughout the cosmos were as large as the one in quantum spin ices “the periodic table would only have 10 elements,” says theoretical physicist Christopher Laumann of Boston University (US). “And it probably would be hard to make people; there wouldn’t be enough richness to chemistry.”

    Quantum spin ices are a class of substances in which particles can’t agree. The materials are made up of particles with spin, a quantum version of angular momentum, which makes them magnetic. In a normal material, particles would come to a consensus below a certain temperature, with the magnetic poles lining up in either the same direction or in alternating directions. But in quantum spin ices, the particles are arranged in such a way that the magnetic poles, or equivalently the spins, can’t agree even at a temperature of absolute zero (SN: 2/13/11).

    The impasse occurs because of the materials’ geometry: The particles are located at the corners of an array of pyramids that are connected at the corners. Conflicts between multiple sets of neighbors mean that the closest these particles can get to harmony is arranging themselves so that two spins face out from each pyramid, and two face in.

    2
    In quantum spin ices, particles (black dots) are located at the corners of an array of pyramids (red). Normally, the spins of the particles (green arrows) arrange so that two are pointing into the pyramid and two out. If that rule is broken, as illustrated, quasiparticles called spinons (orange and blue) form.S.D. Pace et al/PRL 2021.

    This uneasy truce can give rise to disturbances that behave like particles within the material, or quasiparticles (SN: 10/3/14). Flip particles’ spins around and you can get what are called spinons, quasiparticles that can move through the material and interact with other spinons in a manner akin to electrons and other charged particles found in the world outside the material. The material re-creates the theory of quantum electrodynamics, the piece of particles physics’ standard model that hashes out how electrically charged particles do their thing. But the specifics, including the fine-structure constant, don’t necessarily match those in the wider universe.

    So Laumann and colleagues set out to calculate the fine-structure constant in quantum spin ices for the first time. The team pegged the number at about 1/10, instead of 1/137. What’s more, the researchers found that they could change the value of the fine-structure constant by tweaking the properties of the theoretical material. That could help scientists study the effects of altering the fine-structure constant — a test that’s well out of reach in our own universe, where the fine-structure constant is fixed.

    Unfortunately scientists haven’t yet found a material that definitively qualifies as quantum spin ice. But one much-studied prospect is a group of minerals called pyrochlores, which have magnetic ions, or electrically charged atoms, arranged in the appropriate pyramid configuration. Scientists might also be able to study the materials using a quantum computer or another quantum device designed to simulate quantum spin ices (SN: 6/29/17).

    If scientists succeed in creating quantum spin ice, the materials could reveal how quantum electrodynamics and the standard model would work in a universe with a much larger fine-structure constant. “That would be the hope,” says condensed matter theorist Shivaji Sondhi of the University of Oxford, who was not involved with the research. “It’s interesting to be able to make a fake standard model … and ask what would happen.”

    See the full article here .


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  • richardmitnick 1:56 pm on September 22, 2021 Permalink | Reply
    Tags: "Simplifying quantum systems", Although redundancy renders the system more stable it also makes it exponentially more complex – and in turn much more susceptible to error., If only it were less prone to error quantum physics might already be giving us instant solutions to seemingly unsolvable problems., In crude terms our digitally driven information society is based on a simple binary opposition: 0 or 1., It is little wonder that quantum physics should exercise a fascination far beyond its immediate circle., It will take some time before a quantum computer can solve practical problems beyond the realm of quantum physics., One potential route is the use of free electrons in semiconductor materials., Quantum Physics, , Topological quantum systems offer an especially neat example of how in physics theory and experiment can be mutually enriching.   

    From Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich] (CH): “Simplifying quantum systems” 

    From Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich] (CH)

    22.09.2021
    Felix Würsten

    If only it were less prone to error quantum physics might already be giving us instant solutions to seemingly unsolvable problems. ETH researchers are therefore working to develop systems that are more robust.

    1
    Quantum systems require sophisticated control technology, a lot of engineering know-​how and a better understanding of the physical correlations. (Photograph: Heidi Hostettler)

    In crude terms our digitally driven information society is based on a simple binary opposition: 0 or 1. But what happens when other alternatives exist alongside these polar opposites? Might this give rise to a whole raft of different states and enable us to process complex information much faster?

    It is precisely the prospect of going beyond conventional methods of data processing that has inspired such high hopes in the field of quantum physics – not only on the part of scientists in basic and theoretical research, but also among the CEOs of major corporations. Were this vision to materialise, and computers behave in accordance with the laws of quantum mechanics, it would open the door to a whole new world of applications. For example, such a powerful system would be able to determine the mechanism of proteins at a radically faster rate than a conventional computer could ever hope to achieve. This, in turn, would massively accelerate the development of new medicines.

    A rocky road

    Given such prospects, it is little wonder that quantum physics should exercise a fascination far beyond its immediate circle. Yet the road that will take us to a quantum computer capable of answering everyday questions is a rocky one – and much longer than many are prepared to admit. “We’re talking about decades, not years, before we reach that point,” says Jonathan Home, Professor of Experimental Quantum Optics and Photonics at ETH Zürich. And Professor Home is one of those working in a field in which quantum research is relatively far along. He uses individual atoms as qubits. These are the basic units of information used by a quantum computer to perform calculations. Home uses beryllium and calcium atoms held in special electrical ion traps. These are then manipulated with a laser according to the laws of quantum mechanics. “Atoms are great systems for information processing because they can be isolated – and because, provided they remain isolated, they can store quantum information for a couple of seconds or even minutes,” he explains.

    In order to be able to use this information, however, these fragile quantum objects have to be reconnected with the everyday physical world. During this step, even the slightest anomalies can corrupt the entire system. The question is, therefore, how to reduce this susceptibility to error and, at the same time, increase the number of qubits.

    Simpler and more robust

    An obvious approach is to equip the systems with a degree of redundancy, i.e. to link several physical qubits to a single logical qubit. But this has a major drawback. Although redundancy renders the system more stable it also makes it exponentially more complex – and in turn much more susceptible to error.

    This requires not only sophisticated control technology and a lot of engineering know-​how but also a better understanding of the physical correlations. According to Home, the development of quantum computers has already yielded concrete benefits, even if today’s technology is still far removed from being able to investigate protein structures: “In essence, our experiments pose an endurance test for the physical theories. The results then provide us with new insights as to how the quantum world works.” One of ETH’s big strengths is that researchers here are working on very different approaches. The ion traps used by Home are just one of a number of routes that could deliver a breakthrough. Superconducting circuits are another promising option. “It’s highly unusual for one university to be pursuing so many different approaches,” says Home.

    Highly specialised infrastructure

    In common with his colleagues, Home has big hopes for the planned physics building on the Hönggerberg campus. Funded by an endowment from Walter Haefner, this will feature highly specialised laboratories that are exceptionally well isolated from outside interference. It is here that scientists will attempt to push back the boundaries of quantum research. In so doing, they will also explore ideas that are still very much in their infancy.

    One potential route is the use of free electrons in semiconductor materials. These are able to move freely of the influence of the crystal lattice structure and exhibit quantum mechanical properties that can be used for processing information. “But for this purpose, the semiconductors have to be extremely pure,” explains Werner Wegscheider, who as Professor of Solid State Physics has experience in producing these specialised materials. He uses a vacuum chamber to build customised semiconductors atom by atom. “We make the world’s purest semiconductors,” he says with pride. Such materials can exhibit completely new properties. When cooled to a very low temperature and exposed to a magnetic field, the free electrons condense to form a quasiparticle. In other words, they collectively behave in the manner of a single particle and can therefore be described mathematically. Researchers have good reason to believe that such topological quantum systems are more resistant to perturbation than other quantum objects – which is precisely why they may be less prone to error.

    A worthwhile effort

    Topological quantum systems offer an especially neat example of how in physics theory and experiment can be mutually enriching. The basic quantum Hall effect underpinning these systems was discovered experimentally. This effect was then described theoretically. The resulting theory subsequently led to the prediction of the topological states about which researchers are currently so excited. It has yet to be experimentally verified whether these theoretically predicted states actually exist in practice. If experimental physicists can demonstrate this, they may soon be returning the problem for additional theoretical elaboration.

    Like Home, Wegscheider warns it will take some time before a quantum computer can solve practical problems beyond the realm of quantum physics. “Three years ago, I was still sceptical, but now I’m pretty confident that we’ll get there,” he says.

    At present, it is still unclear which of the various approaches will ultimately prevail. The answer may well lie in a mix of different solutions – semiconductors with superconducting circuits, for example. “When these two options are combined, you get quasiparticles known as Majorana fermions, which are thought to be less susceptible to error,” says Wegscheider. Yiwen Chu, Assistant Professor of Hybrid Quantum Systems, is investigating combinations of different quantum systems. “There’s a whole range of quantum objects, such as photons, ions or even superconducting circuits,” she explains. “All have their specific strengths, but also disadvantages. The question is how to bring these elements together in a way that combines their strengths.”

    Bridging the gap

    Her model is the classic computer, which uses, for example, a silicon chip to process information and optical fibre to transfer the data. By analogy, a quantum system might use superconducting circuits to process data, which would then be transferred by photons. “But it turns out that these two quantum objects are not particularly compatible,” says Chu. What is needed, therefore, is something to bridge the gap. Chu and her research group are currently investigating the use of small crystals for this purpose. As mechanical objects, they are able to communicate with both sides by means of acoustic vibrations.

    At the same time, it may well be that these crystals themselves are capable of storing and processing quantum information. “The crystals use acoustic vibrations, which are much slower than light waves, so we could use them to build smaller qubits,” she explains. Yet her chief aim here is not to accommodate as many qubits as possible on a given surface. The advantage is rather that these crystals can be isolated from one another much more easily than, for example, superconducting circuits. The greater degree of isolation prevents an unwanted loss of information, which in turn helps reduce the susceptibility to error. Yet the greatest challenge of all is that as more and more qubits are connected together, the system itself has to become increasingly complex.

    Yet it would be wrong, she says, to look upon the quantum computer as purely an engineering problem. “There are also a lot of unanswered questions on the physics side of the equation.” One of these is whether the transition between the worlds of classical and quantum physics is continuous or abrupt. “We don’t yet have a definitive answer to this problem,” says Chu. “But either way, it’s going be an exciting time for us physicists!”

    See the full article here .

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    ETH Zurich campus
    Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich] (CH) is a public research university in the city of Zürich, Switzerland. Founded by the Swiss Federal Government in 1854 with the stated mission to educate engineers and scientists, the school focuses exclusively on science, technology, engineering and mathematics. Like its sister institution Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne](CH) , it is part of the Swiss Federal Institutes of Technology Domain (ETH Domain)) , part of the Swiss Federal Department of Economic Affairs, Education and Research [EAER][Eidgenössisches Departement für Wirtschaft, Bildung und Forschung] [Département fédéral de l’économie, de la formation et de la recherche] (CH).

    The university is an attractive destination for international students thanks to low tuition fees of 809 CHF per semester, PhD and graduate salaries that are amongst the world’s highest, and a world-class reputation in academia and industry. There are currently 22,200 students from over 120 countries, of which 4,180 are pursuing doctoral degrees. In the 2021 edition of the QS World University Rankings ETH Zürich is ranked 6th in the world and 8th by the Times Higher Education World Rankings 2020. In the 2020 QS World University Rankings by subject it is ranked 4th in the world for engineering and technology (2nd in Europe) and 1st for earth & marine science.

    As of November 2019, 21 Nobel laureates, 2 Fields Medalists, 2 Pritzker Prize winners, and 1 Turing Award winner have been affiliated with the Institute, including Albert Einstein. Other notable alumni include John von Neumann and Santiago Calatrava. It is a founding member of the IDEA League and the International Alliance of Research Universities (IARU) and a member of the CESAER network.

    ETH Zürich was founded on 7 February 1854 by the Swiss Confederation and began giving its first lectures on 16 October 1855 as a polytechnic institute (eidgenössische polytechnische Schule) at various sites throughout the city of Zurich. It was initially composed of six faculties: architecture, civil engineering, mechanical engineering, chemistry, forestry, and an integrated department for the fields of mathematics, natural sciences, literature, and social and political sciences.

    It is locally still known as Polytechnikum, or simply as Poly, derived from the original name eidgenössische polytechnische Schule, which translates to “federal polytechnic school”.

    ETH Zürich is a federal institute (i.e., under direct administration by the Swiss government), whereas the University of Zürich [Universität Zürich ] (CH) is a cantonal institution. The decision for a new federal university was heavily disputed at the time; the liberals pressed for a “federal university”, while the conservative forces wanted all universities to remain under cantonal control, worried that the liberals would gain more political power than they already had. In the beginning, both universities were co-located in the buildings of the University of Zürich.

    From 1905 to 1908, under the presidency of Jérôme Franel, the course program of ETH Zürich was restructured to that of a real university and ETH Zürich was granted the right to award doctorates. In 1909 the first doctorates were awarded. In 1911, it was given its current name, Eidgenössische Technische Hochschule. In 1924, another reorganization structured the university in 12 departments. However, it now has 16 departments.

    ETH Zürich, EPFL (Swiss Federal Institute of Technology in Lausanne) [École polytechnique fédérale de Lausanne](CH), and four associated research institutes form the Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) with the aim of collaborating on scientific projects.

    Reputation and ranking

    ETH Zürich is ranked among the top universities in the world. Typically, popular rankings place the institution as the best university in continental Europe and ETH Zürich is consistently ranked among the top 1-5 universities in Europe, and among the top 3-10 best universities of the world.

    Historically, ETH Zürich has achieved its reputation particularly in the fields of chemistry, mathematics and physics. There are 32 Nobel laureates who are associated with ETH Zürich, the most recent of whom is Richard F. Heck, awarded the Nobel Prize in chemistry in 2010. Albert Einstein is perhaps its most famous alumnus.

    In 2018, the QS World University Rankings placed ETH Zürich at 7th overall in the world. In 2015, ETH Zürich was ranked 5th in the world in Engineering, Science and Technology, just behind the Massachusetts Institute of Technology(US), Stanford University(US) and University of Cambridge(UK). In 2015, ETH Zürich also ranked 6th in the world in Natural Sciences, and in 2016 ranked 1st in the world for Earth & Marine Sciences for the second consecutive year.

    In 2016, Times Higher Education World University Rankings ranked ETH Zürich 9th overall in the world and 8th in the world in the field of Engineering & Technology, just behind the Massachusetts Institute of Technology(US), Stanford University(US), California Institute of Technology(US), Princeton University(US), University of Cambridge(UK), Imperial College London(UK) and University of Oxford(UK) .

    In a comparison of Swiss universities by swissUP Ranking and in rankings published by CHE comparing the universities of German-speaking countries, ETH Zürich traditionally is ranked first in natural sciences, computer science and engineering sciences.

    In the survey CHE ExcellenceRanking on the quality of Western European graduate school programs in the fields of biology, chemistry, physics and mathematics, ETH Zürich was assessed as one of the three institutions to have excellent programs in all the considered fields, the other two being Imperial College London(UK) and the University of Cambridge(UK), respectively.

     
  • richardmitnick 9:53 am on September 18, 2021 Permalink | Reply
    Tags: "UArizona Engineer Awarded $5M to Build Quantum-Powered Navigation Tools", , Gaining an Edge on Earth and Beyond, Many electronics including cellphones are equipped with tiny gyroscopes and accelerometers that enable features like automatic screen rotation and directional pointers for GPS apps., , , Quantum Physics, Quantum technology and AI innovation are a priority for the National Science Foundation, The National Science Foundation (US) Convergence Accelerator, , Upgrading Gyroscopes and Accelerometers   

    From University of Arizona (US) : “UArizona Engineer Awarded $5M to Build Quantum-Powered Navigation Tools” 

    From University of Arizona (US)

    9.16.21
    Emily Dieckman, College of Engineering

    Funded by The National Science Foundation (US) Convergence Accelerator Program the Quantum Sensors project aims to make space and terrestrial navigation far more sensitive, accurate and affordable.

    1
    Zheshen Zhang. Credit: Emily Dieckman.

    Zheshen Zhang, a University of Arizona assistant professor of materials science and engineering, is leading a $5 million quantum technology project to advance navigation for autonomous vehicles and spacecraft, as well as measurement of otherworldly materials such as Dark Matter and gravitational waves.

    The National Science Foundation’s Convergence Accelerator Program, which fast-tracks multidisciplinary efforts to solve real-world problems, is funding the Quantum Sensors project.

    In September 2020, 29 U.S. teams received phase I funding to develop solutions in either quantum technology or artificial intelligence-driven data sharing and modeling. Ten prototypes have advanced to phase II, each receiving $5 million, including two projects led by UArizona researchers – Zhang’s project and another by hydrology and atmospheric sciences assistant professor Laura Condon.

    “Quantum technology and AI innovation are a priority for the National Science Foundation,” said Douglas Maughan, head of the NSF Convergence Accelerator program. “Today’s scientific priorities and national-scale societal challenges cannot be solved by a single discipline. Instead, the merging of new ideas, techniques and approaches, plus the Convergence Accelerator’s innovation curriculum, enables teams to speed their research into application. We are excited to welcome Quantum Sensors into phase II and to assist them in applying our program fundamentals to ensure their solution provides a positive impact on society at large.”

    Upgrading Gyroscopes and Accelerometers

    The objects we interact with in our daily lives adhere to classic laws of physics, like gravity and thermodynamics. Quantum physics, however, has different rules, and objects in quantum states can exhibit strange but useful properties. For example, when two particles are linked by quantum entanglement, anything that happens to one particle affects the other, no matter how far apart they are. This means probes in two locations can share information, allowing for more precise measurements. Or, while “classical” light emits photons at random intervals, scientists can induce a quantum state called “squeezed” light to make photon emission more regular and reduce uncertainty – or “noise” – in measurements.

    The Quantum Sensors project will take advantage of quantum states to create ultrasensitive gyroscopes, accelerometers and other sensors. Gyroscopes are used in navigation of aircraft and other vehicles to maintain balance as orientation shifts. In tandem, accelerometers measure vibration or acceleration of motion. These navigation-grade gyroscopes and accelerometers are light-based and can be extremely precise, but they are bulky and expensive.

    Many electronics including cellphones are equipped with tiny gyroscopes and accelerometers that enable features like automatic screen rotation and directional pointers for GPS apps. At this scale, gyroscopes are made up of micromechanical parts, rather than lasers or other light sources, rendering them far less precise. Zhang and his team aim to develop chip-scale light-based gyroscopes and accelerometers to outperform current mechanical methods. However, the detection of light at this scale is limited by the laws of quantum physics, presenting a fundamental performance limit for such optical gyroscopes and accelerometers.

    Rather than combat these quantum limitations with classical resources, Zhang and his team are fighting fire with fire, so to speak, by using quantum resources. For example, the stability of squeezed light can counterbalance the uncertainty of quantum fluctuations, which are temporary changes in variables such as position and momentum.

    “The fundamental quantum limit is induced by quantum fluctuations, but this limit can be broken using a quantum state of light, like entangled photons or squeezed light, for the laser itself,” said Zhang, director of The University of Arizona (US) Quantum Information and Materials Group. “With this method, we can arrive at much better measurements.”

    Gaining an Edge on Earth and Beyond

    The benefits of extremely precise measurements are numerous. If a self-driving car could determine its exact location and speed using only a compact, quantum-enhanced, onboard gyroscope and accelerometer, it wouldn’t need to rely on GPS to navigate. A self-contained navigation system would protect the car from hackers and provide more stability. The same goes for navigation of spacecraft and terrestrial vehicles sent to other planets.

    “In both space-based and terrestrial technologies, there are a lot of fluctuations. In an urban environment, you might lose GPS signal driving through a tunnel,” Zhang said. “This method could capture information not provided by a GPS. GPS tells you where you are, but it doesn’t tell you your altitude, the direction your vehicle is driving or the angle of the road. With all of this information, the safety of the passengers would be ensured.”

    Zhang is collaborating with partners at General Dynamics Mission Systems, Honeywell, NASA JPL-Caltech (US) The National Institute of Standards and Technology (US), Purdue University (US), The Texas A&M University (US), The University of California-Los Angeles (US) and Morgan State University (US).

    “We are excited to work with the University of Arizona on this NSF Convergence Accelerator project,” said Jianfeng Wu, Honeywell representative and project co-principal investigator. “The integrated entangled light sources can reduce the noise floor and enable the navigation-grade performance from chip-scale gyroscopes. The success of this program will significantly disrupt the current gyroscope landscape from many perspectives.”

    Because precise navigation would directly affect 700 million people worldwide, researchers estimate that quantum sensors could create a $2.5 billion market by 2035. They also expect that the precision and stability offered by the technology will give researchers a way to measure previously unmeasurable forces, such as gravitational waves and Dark Matter.

    “As a leading international research university bringing the Fourth Industrial Revolution to life, we are deeply committed to advance amazing new information technologies like quantum networking to benefit humankind,” said University of Arizona President Robert C. Robbins. “The University of Arizona is an internationally recognized leader in this area, and I look forward to seeing how Dr. Zhang’s Quantum Sensors project moves us forward in addressing real-world challenges with quantum technology.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    As of 2019, the University of Arizona (US) enrolled 45,918 students in 19 separate colleges/schools, including the UArizona College of Medicine in Tucson and Phoenix and the James E. Rogers College of Law, and is affiliated with two academic medical centers (Banner – University Medical Center Tucson and Banner – University Medical Center Phoenix). UArizona is one of three universities governed by the Arizona Board of Regents. The university is part of the Association of American Universities and is the only member from Arizona, and also part of the Universities Research Association(US). The university is classified among “R1: Doctoral Universities – Very High Research Activity”.

    Known as the Arizona Wildcats (often shortened to “Cats”), the UArizona’s intercollegiate athletic teams are members of the Pac-12 Conference of the NCAA. UArizona athletes have won national titles in several sports, most notably men’s basketball, baseball, and softball. The official colors of the university and its athletic teams are cardinal red and navy blue.

    After the passage of the Morrill Land-Grant Act of 1862, the push for a university in Arizona grew. The Arizona Territory’s “Thieving Thirteenth” Legislature approved the UArizona in 1885 and selected the city of Tucson to receive the appropriation to build the university. Tucson hoped to receive the appropriation for the territory’s mental hospital, which carried a $100,000 allocation instead of the $25,000 allotted to the territory’s only university (Arizona State University(US) was also chartered in 1885, but it was created as Arizona’s normal school, and not a university). Flooding on the Salt River delayed Tucson’s legislators, and by they time they reached Prescott, back-room deals allocating the most desirable territorial institutions had been made. Tucson was largely disappointed with receiving what was viewed as an inferior prize.

    With no parties willing to provide land for the new institution, the citizens of Tucson prepared to return the money to the Territorial Legislature until two gamblers and a saloon keeper decided to donate the land to build the school. Construction of Old Main, the first building on campus, began on October 27, 1887, and classes met for the first time in 1891 with 32 students in Old Main, which is still in use today. Because there were no high schools in Arizona Territory, the university maintained separate preparatory classes for the first 23 years of operation.

    Research

    UArizona is classified among “R1: Doctoral Universities – Very high research activity”. UArizona is the fourth most awarded public university by National Aeronautics and Space Administration(US) for research. UArizona was awarded over $325 million for its Lunar and Planetary Laboratory (LPL) to lead NASA’s 2007–08 mission to Mars to explore the Martian Arctic, and $800 million for its OSIRIS-REx mission, the first in U.S. history to sample an asteroid.

    The LPL’s work in the Cassini spacecraft orbit around Saturn is larger than any other university globally. The UArizona laboratory designed and operated the atmospheric radiation investigations and imaging on the probe. UArizona operates the HiRISE camera, a part of the Mars Reconnaissance Orbiter. While using the HiRISE camera in 2011, UArizona alumnus Lujendra Ojha and his team discovered proof of liquid water on the surface of Mars—a discovery confirmed by NASA in 2015. UArizona receives more NASA grants annually than the next nine top NASA/JPL-Caltech(US)-funded universities combined. As of March 2016, the UArizona’s Lunar and Planetary Laboratory is actively involved in ten spacecraft missions: Cassini VIMS; Grail; the HiRISE camera orbiting Mars; the Juno mission orbiting Jupiter; Lunar Reconnaissance Orbiter (LRO); Maven, which will explore Mars’ upper atmosphere and interactions with the sun; Solar Probe Plus, a historic mission into the Sun’s atmosphere for the first time; Rosetta’s VIRTIS; WISE; and OSIRIS-REx, the first U.S. sample-return mission to a near-earth asteroid, which launched on September 8, 2016.

    UArizona students have been selected as Truman, Rhodes, Goldwater, and Fulbright Scholars. According to The Chronicle of Higher Education, UArizona is among the top 25 producers of Fulbright awards in the U.S.

    UArizona is a member of the Association of Universities for Research in Astronomy(US), a consortium of institutions pursuing research in astronomy. The association operates observatories and telescopes, notably Kitt Peak National Observatory(US) just outside Tucson. Led by Roger Angel, researchers in the Steward Observatory Mirror Lab at UArizona are working in concert to build the world’s most advanced telescope. Known as the Giant Magellan Telescope(CL), it will produce images 10 times sharper than those from the Earth-orbiting Hubble Telescope.

    Giant Magellan Telescope, 21 meters, to be at the NOIRLab(US) National Optical Astronomy Observatory(US) Carnegie Institution for Science’s(US) Las Campanas Observatory(CL), some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.


    The telescope is set to be completed in 2021. GMT will ultimately cost $1 billion. Researchers from at least nine institutions are working to secure the funding for the project. The telescope will include seven 18-ton mirrors capable of providing clear images of volcanoes and riverbeds on Mars and mountains on the moon at a rate 40 times faster than the world’s current large telescopes. The mirrors of the Giant Magellan Telescope will be built at UArizona and transported to a permanent mountaintop site in the Chilean Andes where the telescope will be constructed.

    Reaching Mars in March 2006, the Mars Reconnaissance Orbiter contained the HiRISE camera, with Principal Investigator Alfred McEwen as the lead on the project. This National Aeronautics and Space Administration(US) mission to Mars carrying the UArizona-designed camera is capturing the highest-resolution images of the planet ever seen. The journey of the orbiter was 300 million miles. In August 2007, the UArizona, under the charge of Scientist Peter Smith, led the Phoenix Mars Mission, the first mission completely controlled by a university. Reaching the planet’s surface in May 2008, the mission’s purpose was to improve knowledge of the Martian Arctic. The Arizona Radio Observatory(US), a part of UArizona Department of Astronomy Steward Observatory(US), operates the Submillimeter Telescope on Mount Graham.

    The National Science Foundation(US) funded the iPlant Collaborative in 2008 with a $50 million grant. In 2013, iPlant Collaborative received a $50 million renewal grant. Rebranded in late 2015 as “CyVerse”, the collaborative cloud-based data management platform is moving beyond life sciences to provide cloud-computing access across all scientific disciplines.
    In June 2011, the university announced it would assume full ownership of the Biosphere 2 scientific research facility in Oracle, Arizona, north of Tucson, effective July 1. Biosphere 2 was constructed by private developers (funded mainly by Texas businessman and philanthropist Ed Bass) with its first closed system experiment commencing in 1991. The university had been the official management partner of the facility for research purposes since 2007.

    U Arizona mirror lab-Where else in the world can you find an astronomical observatory mirror lab under a football stadium?

    University of Arizona’s Biosphere 2, located in the Sonoran desert. An entire ecosystem under a glass dome? Visit our campus, just once, and you’ll quickly understand why the UA is a university unlike any other.

     
  • richardmitnick 11:58 am on September 7, 2021 Permalink | Reply
    Tags: "New ‘vortex beams’ of atoms and molecules are the first of their kind", , , Quantum Physics   

    From “Science News (US) : “New ‘vortex beams’ of atoms and molecules are the first of their kind” 

    From “Science News (US)

    September 2, 2021
    Emily Conover

    1
    Scientists made spiraling beams of atoms and molecules, known as vortex beams, for the first time. Credit: zf L/Moment/Getty Images Plus.

    Scientists previously made twisted beams of light and electrons.

    Scientists already knew how to dish up spiraling beams of light or electrons, known as vortex beams (SN: 1/14/11). Now, the first vortex beams of atoms and molecules are on the menu, researchers report in the Sept. 3 Science.

    Vortex beams made of light or electrons have shown promise for making special types of microscope images and for transmitting information using quantum physics (SN: 8/5/15). But vortex beams of larger particles such as atoms or molecules are so new that the possible applications aren’t yet clear, says physicist Sonja Franke-Arnold of the University of Glasgow (SCT) , who was not involved with the research. “It’s maybe too early to really know what we can do with it.”

    In quantum physics, particles are described by a wave function, a wavelike pattern that allows scientists to calculate the probability of finding a particle in a particular place (SN: 6/8/11). But vortex beams’ waves don’t slosh up and down like ripples on water. Instead, the beams’ particles have wave functions that move in a corkscrewing motion as a beam travels through space. That means the beam carries a rotational oomph known as orbital angular momentum. “This is something really very strange, very nonintuitive,” says physicist Edvardas Narevicius of the Weizmann Institute of Science (IL).

    Narevicius and colleagues created the new beams by passing helium atoms through a grid of specially shaped slit patterns, each just 600 nanometers wide. The team detected a hallmark of vortex beams: a row of doughnut-shaped rings imprinted on a detector by the atoms, in which each doughnut corresponds to a beam with a different orbital angular momentum.

    Another set of doughnuts revealed the presence of vortex beams of helium excimers, molecules created when a helium atom in an excited, or energized, state pairs up with another helium atom.

    2
    A pattern of rings reveals the presence of vortex beams of atoms and molecules. Each doughnut shape corresponds to a beam of helium atoms with a different angular momentum. Two hard-to-see circles from helium molecules sit in between the center dot and the first two doughnuts left and right of the center. Credit: A. Luski et al/Science 2021.

    Next, scientists might investigate what happens when vortex beams of molecules or atoms collide with light, electrons or other atoms or molecules. Such collisions are well-understood for normal particle beams, but not for those with orbital angular momentum. Similar vortex beams made with protons might also serve as a method for probing the subatomic particle’s mysterious innards (SN: 4/18/17).

    In physics, “most important things are achieved when we are revisiting known phenomena with a fresh perspective,” says physicist Ivan Madan of EPFL (Swiss Federal Institute of Technology in Lausanne) [École polytechnique fédérale de Lausanne](CH), who was not involved with the research. “And, for sure, this experiment allows us to do that.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

     
  • richardmitnick 8:54 am on August 26, 2021 Permalink | Reply
    Tags: "Light-matter interactions propel quantum technologies forward", A photon can be absorbed to turn a pair of atoms into a molecule then emitted back then reabsorbed multiple times., , QED: cavity quantum electrodynamics, Quantum Physics, , The pair-photon system forms a new type of ‘particle’ – technically an excitation – which we call ‘pair-polariton’.   

    From Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH): “Light-matter interactions propel quantum technologies forward” 

    From Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH)

    26.08.21
    Nik Papageorgiou

    Physicists at EPFL have found a way to get photons to interact with pairs of atoms for the first time. The breakthrough is important for the field of cavity quantum electrodynamics (QED), a cutting-edge field leading the way to quantum technologies.

    1
    A collection of atom pairs inside an optical cavity formed by a pair of mirrors facing each other. The light trapped between the mirrors turns pairs of atoms into molecules in a coherent way. Credit: Ella Maru studio.

    There is no doubt that we are moving steadily toward an era of technologies based on quantum physics. But to get there, we first have to master the ability to make light interact with matter – or more technically, photons with atoms.

    This has already been achieved to some degree, giving us the cutting-edge field of cavity quantum electrodynamics (QED), which is already used in quantum networks and quantum information processing. Nonetheless, there are still a long way to go. Current light-matter interactions are limited to individual atoms, which limits our ability to study them in the sort of complex systems involved in quantum-based technologies.

    In a paper published in Nature, researchers from the group of Jean-Philippe Brantut at EPFL’s School of Basic Sciences have found a way to get photons to ‘mix’ with pairs of atoms at ultra-low temperatures.

    The researchers used what is known as a Fermi gas, a state of matter made of atoms that resembles that of electrons in materials. “In the absence of photons, the gas can be prepared in a state where atoms interact very strongly with each other, forming loosely bound pairs,” explains Brantut. “As light is sent onto the gas, some of these pairs can be turned into chemically bound molecules by absorbing with photons.”

    A key concept in this new effect is that that it happens “coherently”, which means that photon can be absorbed to turn a pair of atoms into a molecule then emitted back then reabsorbed multiple times. “This implies the pair-photon system forms a new type of ‘particle’ – technically an excitation – which we call ‘pair-polariton’,” says Brantut. “This is made possible in our system, where photons are confined in an ‘optical cavity’ – a closed box that forces them to interact strongly with the atoms.”

    The hybrid pair-polaritons take on some of the properties of photons, meaning that they can be measured with optical methods. They also take on some of the properties of the Fermi gas, like the number of atom pairs it had originally before the incoming photons.

    “Some of the very intricate properties of the gas are translated onto optical properties, which can be measured in a direct way, and even without perturbing the system,” says Brantut. “A future application would be in quantum chemistry, since we demonstrate that some chemical reactions can be coherently produced using single photons.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    EPFL bloc

    EPFL campus

    The Swiss Federal Institute of Technology in Lausanne [EPFL-École polytechnique fédérale de Lausanne] (CH) is a research institute and university in Lausanne, Switzerland, that specializes in natural sciences and engineering. It is one of the two Swiss Federal Institutes of Technology, and it has three main missions: education, research and technology transfer.

    The QS World University Rankings ranks EPFL(CH) 14th in the world across all fields in their 2020/2021 ranking, whereas Times Higher Education World University Rankings ranks EPFL(CH) as the world’s 19th best school for Engineering and Technology in 2020.

    EPFL(CH) is located in the French-speaking part of Switzerland; the sister institution in the German-speaking part of Switzerland is the Swiss Federal Institute of Technology ETH Zürich [Eidgenössische Technische Hochschule Zürich)](CH) . Associated with several specialized research institutes, the two universities form the Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) which is directly dependent on the Federal Department of Economic Affairs, Education and Research. In connection with research and teaching activities, EPFL(CH) operates a nuclear reactor CROCUS; a Tokamak Fusion reactor; a Blue Gene/Q Supercomputer; and P3 bio-hazard facilities.

    The roots of modern-day EPFL(CH) can be traced back to the foundation of a private school under the name École spéciale de Lausanne in 1853 at the initiative of Lois Rivier, a graduate of the École Centrale Paris (FR) and John Gay the then professor and rector of the Académie de Lausanne. At its inception it had only 11 students and the offices was located at Rue du Valentin in Lausanne. In 1869, it became the technical department of the public Académie de Lausanne. When the Académie was reorganised and acquired the status of a university in 1890, the technical faculty changed its name to École d’ingénieurs de l’Université de Lausanne. In 1946, it was renamed the École polytechnique de l’Université de Lausanne (EPUL). In 1969, the EPUL was separated from the rest of the University of Lausanne and became a federal institute under its current name. EPFL(CH), like ETH Zürich(CH), is thus directly controlled by the Swiss federal government. In contrast, all other universities in Switzerland are controlled by their respective cantonal governments. Following the nomination of Patrick Aebischer as president in 2000, EPFL(CH) has started to develop into the field of life sciences. It absorbed the Swiss Institute for Experimental Cancer Research (ISREC) in 2008.

    In 1946, there were 360 students. In 1969, EPFL(CH) had 1,400 students and 55 professors. In the past two decades the university has grown rapidly and as of 2012 roughly 14,000 people study or work on campus, about 9,300 of these being Bachelor, Master or PhD students. The environment at modern day EPFL(CH) is highly international with the school attracting students and researchers from all over the world. More than 125 countries are represented on the campus and the university has two official languages, French and English.

    Organization

    EPFL is organised into eight schools, themselves formed of institutes that group research units (laboratories or chairs) around common themes:

    School of Basic Sciences (SB, Jan S. Hesthaven)

    Institute of Mathematics (MATH, Victor Panaretos)
    Institute of Chemical Sciences and Engineering (ISIC, Emsley Lyndon)
    Institute of Physics (IPHYS, Harald Brune)
    European Centre of Atomic and Molecular Computations (CECAM, Ignacio Pagonabarraga Mora)
    Bernoulli Center (CIB, Nicolas Monod)
    Biomedical Imaging Research Center (CIBM, Rolf Gruetter)
    Interdisciplinary Center for Electron Microscopy (CIME, Cécile Hébert)
    Max Planck-EPFL Centre for Molecular Nanosciences and Technology (CMNT, Thomas Rizzo)
    Swiss Plasma Center (SPC, Ambrogio Fasoli)
    Laboratory of Astrophysics (LASTRO, Jean-Paul Kneib)

    School of Engineering (STI, Ali Sayed)

    Institute of Electrical Engineering (IEL, Giovanni De Micheli)
    Institute of Mechanical Engineering (IGM, Thomas Gmür)
    Institute of Materials (IMX, Michaud Véronique)
    Institute of Microengineering (IMT, Olivier Martin)
    Institute of Bioengineering (IBI, Matthias Lütolf)

    School of Architecture, Civil and Environmental Engineering (ENAC, Claudia R. Binder)

    Institute of Architecture (IA, Luca Ortelli)
    Civil Engineering Institute (IIC, Eugen Brühwiler)
    Institute of Urban and Regional Sciences (INTER, Philippe Thalmann)
    Environmental Engineering Institute (IIE, David Andrew Barry)

    School of Computer and Communication Sciences (IC, James Larus)

    Algorithms & Theoretical Computer Science
    Artificial Intelligence & Machine Learning
    Computational Biology
    Computer Architecture & Integrated Systems
    Data Management & Information Retrieval
    Graphics & Vision
    Human-Computer Interaction
    Information & Communication Theory
    Networking
    Programming Languages & Formal Methods
    Security & Cryptography
    Signal & Image Processing
    Systems

    School of Life Sciences (SV, Gisou van der Goot)

    Bachelor-Master Teaching Section in Life Sciences and Technologies (SSV)
    Brain Mind Institute (BMI, Carmen Sandi)
    Institute of Bioengineering (IBI, Melody Swartz)
    Swiss Institute for Experimental Cancer Research (ISREC, Douglas Hanahan)
    Global Health Institute (GHI, Bruno Lemaitre)
    Ten Technology Platforms & Core Facilities (PTECH)
    Center for Phenogenomics (CPG)
    NCCR Synaptic Bases of Mental Diseases (NCCR-SYNAPSY)

    College of Management of Technology (CDM)

    Swiss Finance Institute at EPFL (CDM-SFI, Damir Filipovic)
    Section of Management of Technology and Entrepreneurship (CDM-PMTE, Daniel Kuhn)
    Institute of Technology and Public Policy (CDM-ITPP, Matthias Finger)
    Institute of Management of Technology and Entrepreneurship (CDM-MTEI, Ralf Seifert)
    Section of Financial Engineering (CDM-IF, Julien Hugonnier)

    College of Humanities (CDH, Thomas David)

    Human and social sciences teaching program (CDH-SHS, Thomas David)

    EPFL Middle East (EME, Dr. Franco Vigliotti)[62]

    Section of Energy Management and Sustainability (MES, Prof. Maher Kayal)

    In addition to the eight schools there are seven closely related institutions

    Swiss Cancer Centre
    Center for Biomedical Imaging (CIBM)
    Centre for Advanced Modelling Science (CADMOS)
    École cantonale d’art de Lausanne (ECAL)
    Campus Biotech
    Wyss Center for Bio- and Neuro-engineering
    Swiss National Supercomputing Centre

     
  • richardmitnick 10:18 am on July 20, 2021 Permalink | Reply
    Tags: "Main Attraction-Scientists Create World’s Thinnest Magnet", 2D magnetism possible at room temperature, , In a final step the graphene is burned away-leaving behind just a single atomic layer of cobalt-doped zinc-oxide., Quantum Physics, , The researchers synthesized the new 2D magnet – called a cobalt-doped van der Waals zinc-oxide magnet – from a solution of graphene oxide; zinc; and cobalt., This development opens up every single atom for examination.   

    From DOE’s Lawrence Berkeley National Laboratory (US) and University of California-Berkeley (US) : “Main Attraction-Scientists Create World’s Thinnest Magnet” 

    From DOE’s Lawrence Berkeley National Laboratory (US)

    and

    University of California-Berkeley (US)

    July 20, 2021
    Theresa Duque
    tnduque@lbl.gov
    (510) 495-2418

    A one-atom-thin 2D magnet developed by Berkeley Lab and UC Berkeley could advance new applications in computing and electronics.

    1
    Illustration of magnetic coupling in a cobalt-doped zinc-oxide monolayer. Red, blue, and yellow spheres represent cobalt, oxygen, and zinc atoms, respectively. Credit: Berkeley Lab.

    The development of an ultrathin magnet that operates at room temperature could lead to new applications in computing and electronics – such as high-density, compact spintronic memory devices – and new tools for the study of quantum physics.

    The ultrathin magnet, which was recently reported in the journal Nature Communications, could make big advances in next-gen memory devices, computing, spintronics, and quantum physics. It was discovered by scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley.

    “We’re the first to make a room-temperature 2D magnet that is chemically stable under ambient conditions,” said senior author Jie Yao, a faculty scientist in Berkeley Lab’s Materials Sciences Division and associate professor of materials science and engineering at UC Berkeley.

    “This discovery is exciting because it not only makes 2D magnetism possible at room temperature, but it also uncovers a new mechanism to realize 2D magnetic materials,” added Rui Chen, a UC Berkeley graduate student in the Yao Research Group and lead author on the study.

    The magnetic component of today’s memory devices is typically made of magnetic thin films. But at the atomic level, these materials are still three-dimensional – hundreds or thousands of atoms thick. For decades, researchers have searched for ways to make thinner and smaller 2D magnets and thus enable data to be stored at a much higher density.

    Previous achievements in the field of 2D magnetic materials have brought promising results. But these early 2D magnets lose their magnetism and become chemically unstable at room temperature.

    “State-of-the-art 2D magnets need very low temperatures to function. But for practical reasons, a data center needs to run at room temperature,” Yao said. “Our 2D magnet is not only the first that operates at room temperature or higher, but it is also the first magnet to reach the true 2D limit: It’s as thin as a single atom!”

    The researchers say that their discovery will also enable new opportunities to study quantum physics. “It opens up every single atom for examination, which may reveal how quantum physics governs each single magnetic atom and the interactions between them,” Yao said.

    The making of a 2D magnet that can take the heat.

    The researchers synthesized the new 2D magnet – called a cobalt-doped van der Waals zinc-oxide magnet – from a solution of graphene oxide; zinc; and cobalt.

    Just a few hours of baking in a conventional lab oven transformed the mixture into a single atomic layer of zinc-oxide with a smattering of cobalt atoms sandwiched between layers of graphene.

    In a final step the graphene is burned away-leaving behind just a single atomic layer of cobalt-doped zinc-oxide.

    “With our material, there are no major obstacles for industry to adopt our solution-based method,” said Yao. “It’s potentially scalable for mass production at lower costs.”

    To confirm that the resulting 2D film is just one atom thick, Yao and his team conducted scanning electron microscopy experiments at Berkeley Lab’s Molecular Foundry [below] to identify the material’s morphology, and transmission electron microscopy (TEM) imaging to probe the material atom by atom.

    X-ray experiments at Berkeley Lab’s Advanced Light Source characterized the 2D material’s magnetic parameters under high temperature.

    DOE’s Lawrence Berkeley National Laboratory (US) Advanced Light Source.

    Additional X-ray experiments at DOE’s SLAC National Accelerator Laboratory’s (US) Stanford Synchrotron Radiation Lightsource verified the electronic and crystal structures of the synthesized 2D magnets.

    SLAC National Accelerator Laboratory (US) Stanford Synchrotron Radiation Lightsource SSRL

    And at DOE’s Argonne National Laboratory’s (US) Center for Nanoscale Materials, the researchers employed TEM to image the 2D material’s crystal structure and chemical composition.

    3
    Argonne National Laboratory’s Center for Nanoscale Materials

    The researchers found that the graphene-zinc-oxide system becomes weakly magnetic with a 5-6% concentration of cobalt atoms. Increasing the concentration of cobalt atoms to about 12% results in a very strong magnet.

    To their surprise, a concentration of cobalt atoms exceeding 15% shifts the 2D magnet into an exotic quantum state of “frustration,” whereby different magnetic states within the 2D system are in competition with each other.

    And unlike previous 2D magnets, which lose their magnetism at room temperature or above, the researchers found that the new 2D magnet not only works at room temperature but also at 100 degrees Celsius (212 degrees Fahrenheit).

    “Our 2D magnetic system shows a distinct mechanism compared to previous 2D magnets,” said Chen. “And we think this unique mechanism is due to the free electrons in zinc oxide.”

    True north: Free electrons keep magnetic atoms on track

    When you command your computer to save a file, that information is stored as a series of ones and zeroes in the computer’s magnetic memory, such as the magnetic hard drive or a flash memory.

    And like all magnets, magnetic memory devices contain microscopic magnets with two poles – north and south, the orientations of which follow the direction of an external magnetic field. Data is written or encoded when these tiny magnets are flipped to the desired directions.

    According to Chen, zinc oxide’s free electrons could act as an intermediary that ensures the magnetic cobalt atoms in the new 2D device continue pointing in the same direction – and thus stay magnetic – even when the host, in this case the semiconductor zinc oxide, is a nonmagnetic material.

    “Free electrons are constituents of electric currents. They move in the same direction to conduct electricity,” Yao added, comparing the movement of free electrons in metals and semiconductors to the flow of water molecules in a stream of water.

    The new material – which can be bent into almost any shape without breaking, and is a million times thinner than a sheet of paper – could help advance the application of spin electronics or spintronics, a new technology that uses the orientation of an electron’s spin rather than its charge to encode data. “Our 2D magnet may enable the formation of ultra-compact spintronic devices to engineer the spins of the electrons,” Chen said.

    “I believe that the discovery of this new, robust, truly two-dimensional magnet at room temperature is a genuine breakthrough,” said co-author Robert Birgeneau, a faculty senior scientist in Berkeley Lab’s Materials Sciences Division and professor of physics at UC Berkeley who co-led the study.

    “Our results are even better than what we expected, which is really exciting. Most of the time in science, experiments can be very challenging,” Yao said. “But when you finally realize something new, it’s always very fulfilling.”

    Co-authors on the paper include researchers from Berkeley Lab, including Alpha N’Diaye and Padraic Shafer of the Advanced Light Source; University of California-Berkeley (US); University of California-Riverside (US); DOE’s Argonne National Laboratory (US); and Nanjing University [南京大學] (CN) and the University of Electronic Science and Technology of China [电子科技大学](CN).

    The Advanced Light Source and Molecular Foundry are DOE national user facilities at Berkeley Lab.

    The Stanford Synchrotron Radiation Lightsource is a DOE national user facility at SLAC National Accelerator Laboratory.

    The Center for Nanoscale Materials is a DOE national user facility at Argonne National Laboratory.

    This work was funded by the DOE Office of Science, the Intel Corporation, and the Bakar Fellows Program at UC Berkeley.

    See the full article here .

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

    Please help promote STEM in your local schools.

    Stem Education Coalition

    The University of California-Berkeley US) is a public land-grant research university in Berkeley, California. Established in 1868 as the state’s first land-grant university, it was the first campus of the University of California (US) system and a founding member of the Association of American Universities (US). Its 14 colleges and schools offer over 350 degree programs and enroll some 31,000 undergraduate and 12,000 graduate students. Berkeley is ranked among the world’s top universities by major educational publications.

    Berkeley hosts many leading research institutes, including the Mathematical Sciences Research Institute and the Space Sciences Laboratory. It founded and maintains close relationships with three national laboratories at DOE’s Lawrence Berkeley National Laboratory(US), DOE’s Lawrence Livermore National Laboratory(US) and DOE’s Los Alamos National Lab(US), and has played a prominent role in many scientific advances, from the Manhattan Project and the discovery of 16 chemical elements to breakthroughs in computer science and genomics. Berkeley is also known for student activism and the Free Speech Movement of the 1960s.

    Berkeley alumni and faculty count among their ranks 110 Nobel laureates (34 alumni), 25 Turing Award winners (11 alumni), 14 Fields Medalists, 28 Wolf Prize winners, 103 MacArthur “Genius Grant” recipients, 30 Pulitzer Prize winners, and 19 Academy Award winners. The university has produced seven heads of state or government; five chief justices, including Chief Justice of the United States Earl Warren; 21 cabinet-level officials; 11 governors; and 25 living billionaires. It is also a leading producer of Fulbright Scholars, MacArthur Fellows, and Marshall Scholars. Berkeley alumni, widely recognized for their entrepreneurship, have founded many notable companies.

    Berkeley’s athletic teams compete in Division I of the NCAA, primarily in the Pac-12 Conference, and are collectively known as the California Golden Bears. The university’s teams have won 107 national championships, and its students and alumni have won 207 Olympic medals.

    Made possible by President Lincoln’s signing of the Morrill Act in 1862, the University of California was founded in 1868 as the state’s first land-grant university by inheriting certain assets and objectives of the private College of California and the public Agricultural, Mining, and Mechanical Arts College. Although this process is often incorrectly mistaken for a merger, the Organic Act created a “completely new institution” and did not actually merge the two precursor entities into the new university. The Organic Act states that the “University shall have for its design, to provide instruction and thorough and complete education in all departments of science, literature and art, industrial and professional pursuits, and general education, and also special courses of instruction in preparation for the professions”.

    Ten faculty members and 40 students made up the fledgling university when it opened in Oakland in 1869. Frederick H. Billings, a trustee of the College of California, suggested that a new campus site north of Oakland be named in honor of Anglo-Irish philosopher George Berkeley. The university began admitting women the following year. In 1870, Henry Durant, founder of the College of California, became its first president. With the completion of North and South Halls in 1873, the university relocated to its Berkeley location with 167 male and 22 female students.

    Beginning in 1891, Phoebe Apperson Hearst made several large gifts to Berkeley, funding a number of programs and new buildings and sponsoring, in 1898, an international competition in Antwerp, Belgium, where French architect Émile Bénard submitted the winning design for a campus master plan.

    20th century

    In 1905, the University Farm was established near Sacramento, ultimately becoming the University of California, Davis. In 1919, Los Angeles State Normal School became the southern branch of the University, which ultimately became the University of California, Los Angeles. By 1920s, the number of campus buildings had grown substantially and included twenty structures designed by architect John Galen Howard.

    In 1917, one of the nation’s first ROTC programs was established at Berkeley and its School of Military Aeronautics began training pilots, including Gen. Jimmy Doolittle. Berkeley ROTC alumni include former Secretary of Defense Robert McNamara and Army Chief of Staff Frederick C. Weyand as well as 16 other generals. In 1926, future fleet admiral Chester W. Nimitz established the first Naval ROTC unit at Berkeley.

    In the 1930s, Ernest Lawrence helped establish the Radiation Laboratory (now DOE’s Lawrence Berkeley National Laboratory (US)) and invented the cyclotron, which won him the Nobel physics prize in 1939. Using the cyclotron, Berkeley professors and Berkeley Lab researchers went on to discover 16 chemical elements—more than any other university in the world. In particular, during World War II and following Glenn Seaborg’s then-secret discovery of plutonium, Ernest Orlando Lawrence’s Radiation Laboratory began to contract with the U.S. Army to develop the atomic bomb. Physics professor J. Robert Oppenheimer was named scientific head of the Manhattan Project in 1942. Along with the Lawrence Berkeley National Laboratory, Berkeley founded and was then a partner in managing two other labs, Los Alamos National Laboratory (1943) and Lawrence Livermore National Laboratory (1952).

    By 1942, the American Council on Education ranked Berkeley second only to Harvard University (US) in the number of distinguished departments.

    In 1952, the University of California reorganized itself into a system of semi-autonomous campuses, with each campus given its own chancellor, and Clark Kerr became Berkeley’s first Chancellor, while Sproul remained in place as the President of the University of California.

    Berkeley gained a worldwide reputation for political activism in the 1960s. In 1964, the Free Speech Movement organized student resistance to the university’s restrictions on political activities on campus—most conspicuously, student activities related to the Civil Rights Movement. The arrest in Sproul Plaza of Jack Weinberg, a recent Berkeley alumnus and chair of Campus CORE, in October 1964, prompted a series of student-led acts of formal remonstrance and civil disobedience that ultimately gave rise to the Free Speech Movement, which movement would prevail and serve as precedent for student opposition to America’s involvement in the Vietnam War.

    In 1982, the Mathematical Sciences Research Institute (MSRI) was established on campus with support from the National Science Foundation and at the request of three Berkeley mathematicians — Shiing-Shen Chern, Calvin Moore and Isadore M. Singer. The institute is now widely regarded as a leading center for collaborative mathematical research, drawing thousands of visiting researchers from around the world each year.

    21st century

    In the current century, Berkeley has become less politically active and more focused on entrepreneurship and fundraising, especially for STEM disciplines.

    Modern Berkeley students are less politically radical, with a greater percentage of moderates and conservatives than in the 1960s and 70s. Democrats outnumber Republicans on the faculty by a ratio of 9:1. On the whole, Democrats outnumber Republicans on American university campuses by a ratio of 10:1.

    In 2007, the Energy Biosciences Institute was established with funding from BP and Stanley Hall, a research facility and headquarters for the California Institute for Quantitative Biosciences, opened. The next few years saw the dedication of the Center for Biomedical and Health Sciences, funded by a lead gift from billionaire Li Ka-shing; the opening of Sutardja Dai Hall, home of the Center for Information Technology Research in the Interest of Society; and the unveiling of Blum Hall, housing the Blum Center for Developing Economies. Supported by a grant from alumnus James Simons, the Simons Institute for the Theory of Computing was established in 2012. In 2014, Berkeley and its sister campus, Univerity of California-San Fransisco (US), established the Innovative Genomics Institute, and, in 2020, an anonymous donor pledged $252 million to help fund a new center for computing and data science.

    Since 2000, Berkeley alumni and faculty have received 40 Nobel Prizes, behind only Harvard and Massachusetts Institute of Technology (US) among US universities; five Turing Awards, behind only MIT and Stanford; and five Fields Medals, second only to Princeton University (US). According to PitchBook, Berkeley ranks second, just behind Stanford University, in producing VC-backed entrepreneurs.

    UC Berkeley Seal

    LBNL campus


    Bringing Science Solutions to the World

    In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) (US) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

    Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (US) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s total costs for FY 2014 were $785 million. A recent study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

    Berkeley Lab was founded in 1931 by Ernest Orlando Lawrence, a University of California-Berkeley (US) physicist who won the 1939 Nobel Prize in physics for his invention of the cyclotron, a circular particle accelerator that opened the door to high-energy physics. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab legacy that continues today.

    History

    1931–1941

    The laboratory was founded on August 26, 1931, by Ernest Lawrence, as the Radiation Laboratory of the University of California, Berkeley, associated with the Physics Department. It centered physics research around his new instrument, the cyclotron, a type of particle accelerator for which he was awarded the Nobel Prize in Physics in 1939.

    LBNL 88 inch cyclotron.


    Throughout the 1930s, Lawrence pushed to create larger and larger machines for physics research, courting private philanthropists for funding. He was the first to develop a large team to build big projects to make discoveries in basic research. Eventually these machines grew too large to be held on the university grounds, and in 1940 the lab moved to its current site atop the hill above campus. Part of the team put together during this period includes two other young scientists who went on to establish large laboratories; J. Robert Oppenheimer founded DOE’s Los Alamos Laboratory (US), and Robert Wilson founded Fermi National Accelerator Laboratory(US).

    1942–1950

    Leslie Groves visited Lawrence’s Radiation Laboratory in late 1942 as he was organizing the Manhattan Project, meeting J. Robert Oppenheimer for the first time. Oppenheimer was tasked with organizing the nuclear bomb development effort and founded today’s Los Alamos National Laboratory to help keep the work secret. At the RadLab, Lawrence and his colleagues developed the technique of electromagnetic enrichment of uranium using their experience with cyclotrons. The “calutrons” (named after the University) became the basic unit of the massive Y-12 facility in Oak Ridge, Tennessee. Lawrence’s lab helped contribute to what have been judged to be the three most valuable technology developments of the war (the atomic bomb, proximity fuse, and radar). The cyclotron, whose construction was stalled during the war, was finished in November 1946. The Manhattan Project shut down two months later.

    1951–2018

    After the war, the Radiation Laboratory became one of the first laboratories to be incorporated into the Atomic Energy Commission (AEC) (now Department of Energy (US). The most highly classified work remained at Los Alamos, but the RadLab remained involved. Edward Teller suggested setting up a second lab similar to Los Alamos to compete with their designs. This led to the creation of an offshoot of the RadLab (now the Lawrence Livermore National Laboratory (US)) in 1952. Some of the RadLab’s work was transferred to the new lab, but some classified research continued at Berkeley Lab until the 1970s, when it became a laboratory dedicated only to unclassified scientific research.

    Shortly after the death of Lawrence in August 1958, the UC Radiation Laboratory (both branches) was renamed the Lawrence Radiation Laboratory. The Berkeley location became the Lawrence Berkeley Laboratory in 1971, although many continued to call it the RadLab. Gradually, another shortened form came into common usage, LBNL. Its formal name was amended to Ernest Orlando Lawrence Berkeley National Laboratory in 1995, when “National” was added to the names of all DOE labs. “Ernest Orlando” was later dropped to shorten the name. Today, the lab is commonly referred to as “Berkeley Lab”.

    The Alvarez Physics Memos are a set of informal working papers of the large group of physicists, engineers, computer programmers, and technicians led by Luis W. Alvarez from the early 1950s until his death in 1988. Over 1700 memos are available on-line, hosted by the Laboratory.

    The lab remains owned by the Department of Energy (US), with management from the University of California (US). Companies such as Intel were funding the lab’s research into computing chips.

    Science mission

    From the 1950s through the present, Berkeley Lab has maintained its status as a major international center for physics research, and has also diversified its research program into almost every realm of scientific investigation. Its mission is to solve the most pressing and profound scientific problems facing humanity, conduct basic research for a secure energy future, understand living systems to improve the environment, health, and energy supply, understand matter and energy in the universe, build and safely operate leading scientific facilities for the nation, and train the next generation of scientists and engineers.

    The Laboratory’s 20 scientific divisions are organized within six areas of research: Computing Sciences; Physical Sciences; Earth and Environmental Sciences; Biosciences; Energy Sciences; and Energy Technologies. Berkeley Lab has six main science thrusts: advancing integrated fundamental energy science; integrative biological and environmental system science; advanced computing for science impact; discovering the fundamental properties of matter and energy; accelerators for the future; and developing energy technology innovations for a sustainable future. It was Lawrence’s belief that scientific research is best done through teams of individuals with different fields of expertise, working together. His teamwork concept is a Berkeley Lab tradition that continues today.

    Berkeley Lab operates five major National User Facilities for the DOE Office of Science (US):

    The Advanced Light Source (ALS) is a synchrotron light source with 41 beam lines providing ultraviolet, soft x-ray, and hard x-ray light to scientific experiments.

    LBNL/ALS


    The ALS is one of the world’s brightest sources of soft x-rays, which are used to characterize the electronic structure of matter and to reveal microscopic structures with elemental and chemical specificity. About 2,500 scientist-users carry out research at ALS every year. Berkeley Lab is proposing an upgrade of ALS which would increase the coherent flux of soft x-rays by two-three orders of magnitude.

    The DOE Joint Genome Institute (US) supports genomic research in support of the DOE missions in alternative energy, global carbon cycling, and environmental management. The JGI’s partner laboratories are Berkeley Lab, DOE’s Lawrence Livermore National Laboratory (US), DOE’s Oak Ridge National Laboratory (US)(ORNL), DOE’s Pacific Northwest National Laboratory (US) (PNNL), and the HudsonAlpha Institute for Biotechnology (US). The JGI’s central role is the development of a diversity of large-scale experimental and computational capabilities to link sequence to biological insights relevant to energy and environmental research. Approximately 1,200 scientist-users take advantage of JGI’s capabilities for their research every year.

    The LBNL Molecular Foundry (US) [above] is a multidisciplinary nanoscience research facility. Its seven research facilities focus on Imaging and Manipulation of Nanostructures; Nanofabrication; Theory of Nanostructured Materials; Inorganic Nanostructures; Biological Nanostructures; Organic and Macromolecular Synthesis; and Electron Microscopy. Approximately 700 scientist-users make use of these facilities in their research every year.

    The DOE’s NERSC National Energy Research Scientific Computing Center (US) is the scientific computing facility that provides large-scale computing for the DOE’s unclassified research programs. Its current systems provide over 3 billion computational hours annually. NERSC supports 6,000 scientific users from universities, national laboratories, and industry.

    DOE’s NERSC National Energy Research Scientific Computing Center(US) at Lawrence Berkeley National Laboratory

    The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

    PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

    NERSC is a DOE Office of Science User Facility.

    The DOE’s Energy Science Network (US) is a high-speed network infrastructure optimized for very large scientific data flows. ESNet provides connectivity for all major DOE sites and facilities, and the network transports roughly 35 petabytes of traffic each month.

    Berkeley Lab is the lead partner in the DOE’s Joint Bioenergy Institute (US) (JBEI), located in Emeryville, California. Other partners are the DOE’s Sandia National Laboratory (US), the University of California (UC) campuses of Berkeley and Davis, the Carnegie Institution for Science (US), and DOE’s Lawrence Livermore National Laboratory (US) (LLNL). JBEI’s primary scientific mission is to advance the development of the next generation of biofuels – liquid fuels derived from the solar energy stored in plant biomass. JBEI is one of three new U.S. Department of Energy (DOE) Bioenergy Research Centers (BRCs).

    Berkeley Lab has a major role in two DOE Energy Innovation Hubs. The mission of the Joint Center for Artificial Photosynthesis (JCAP) is to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide. The lead institution for JCAP is the California Institute of Technology (US) and Berkeley Lab is the second institutional center. The mission of the Joint Center for Energy Storage Research (JCESR) is to create next-generation battery technologies that will transform transportation and the electricity grid. DOE’s Argonne National Laboratory (US) leads JCESR and Berkeley Lab is a major partner.

     
  • richardmitnick 9:11 pm on July 2, 2021 Permalink | Reply
    Tags: "AI Designs Quantum Physics Experiments Beyond What Any Human Has Conceived", , MELVIN had seemingly solved the problem of creating highly complex entangled states involving multiple photons. How?, MELVIN was a machine-learning algorithm., Quantum Physics, , The algorithm had rediscovered a type of experimental arrangement that had been devised in the early 1990s., When two photons interact they become entangled and both can only be mathematically described using a single shared quantum state.   

    From Scientific American : “AI Designs Quantum Physics Experiments Beyond What Any Human Has Conceived” 

    From Scientific American

    July 2, 2021
    Anil Ananthaswamy

    1
    Credit: Getty Images.

    Quantum physicist Mario Krenn remembers sitting in a café in Vienna in early 2016, poring over computer printouts, trying to make sense of what MELVIN had found. MELVIN was a machine-learning algorithm Krenn had built, a kind of artificial intelligence. Its job was to mix and match the building blocks of standard quantum experiments and find solutions to new problems. And it did find many interesting ones. But there was one that made no sense.

    “The first thing I thought was, ‘My program has a bug, because the solution cannot exist,’” Krenn says. MELVIN had seemingly solved the problem of creating highly complex entangled states involving multiple photons (entangled states being those that once made Albert Einstein invoke the specter of “spooky action at a distance”). Krenn and his colleagues had not explicitly provided MELVIN the rules needed to generate such complex states, yet it had found a way. Eventually, he realized that the algorithm had rediscovered a type of experimental arrangement that had been devised in the early 1990s. But those experiments had been much simpler. MELVIN had cracked a far more complex puzzle.

    “When we understood what was going on, we were immediately able to generalize [the solution],” says Krenn, who is now at the University of Toronto (CA). Since then, other teams have started performing the experiments identified by MELVIN, allowing them to test the conceptual underpinnings of quantum mechanics in new ways. Meanwhile Krenn, Anton Zeilinger of the University of Vienna [Universität Wien] (AT) and their colleagues have refined their machine-learning algorithms. Their latest effort, an AI called THESEUS, has upped the ante: it is orders of magnitude faster than MELVIN, and humans can readily parse its output. While it would take Krenn and his colleagues days or even weeks to understand MELVIN’s meanderings, they can almost immediately figure out what THESEUS is saying.

    “It is amazing work,” says theoretical quantum physicist Renato Renner of the Institute for Theoretical Physics at the Swiss Federal Institute of Technology ETH Zürich [Eidgenössische Technische Hochschule Zürich)](CH), who reviewed a 2020 study about THESEUS by Krenn and Zeilinger but was not directly involved in these efforts.

    Krenn stumbled on this entire research program somewhat by accident when he and his colleagues were trying to figure out how to experimentally create quantum states of photons entangled in a very particular manner: When two photons interact, they become entangled, and both can only be mathematically described using a single shared quantum state. If you measure the state of one photon, the measurement instantly fixes the state of the other even if the two are kilometers apart (hence Einstein’s derisive comments on entanglement being “spooky”).

    In 1989 three physicists—Daniel Greenberger, the late Michael Horne and Zeilinger—described an entangled state that came to be known as “GHZ” (after their initials). It involved four photons, each of which could be in a quantum superposition of, say, two states, 0 and 1 (a quantum state called a qubit). In their paper, the GHZ state involved entangling four qubits such that the entire system was in a two-dimensional quantum superposition of states 0000 and 1111. If you measured one of the photons and found it in state 0, the superposition would collapse, and the other photons would also be in state 0. The same went for state 1. In the late 1990s Zeilinger and his colleagues experimentally observed GHZ states using three qubits for the first time.

    Krenn and his colleagues were aiming for GHZ states of higher dimensions. They wanted to work with three photons, where each photon had a dimensionality of three, meaning it could be in a superposition of three states: 0, 1 and 2. This quantum state is called a qutrit. The entanglement the team was after was a three-dimensional GHZ state that was a superposition of states 000, 111 and 222. Such states are important ingredients for secure quantum communications and faster quantum computing. In late 2013 the researchers spent weeks designing experiments on blackboards and doing the calculations to see if their setups could generate the required quantum states. But each time they failed. “I thought, ‘This is absolutely insane. Why can’t we come up with a setup?’” says Krenn says.

    To speed up the process, Krenn first wrote a computer program that took an experimental setup and calculated the output. Then he upgraded the program to allow it to incorporate in its calculations the same building blocks that experimenters use to create and manipulate photons on an optical bench: lasers, nonlinear crystals, beam splitters, phase shifters, holograms, and the like. The program searched through a large space of configurations by randomly mixing and matching the building blocks, performed the calculations and spat out the result. MELVIN was born. “Within a few hours, the program found a solution that we scientists—three experimentalists and one theorist—could not come up with for months,” Krenn says. “That was a crazy day. I could not believe that it happened.”

    Then he gave MELVIN more smarts. Anytime it found a setup that did something useful, MELVIN added that setup to its toolbox. “The algorithm remembers that and tries to reuse it for more complex solutions,” Krenn says.

    It was this more evolved MELVIN that left Krenn scratching his head in a Viennese café. He had set it running with an experimental toolbox that contained two crystals, each capable of generating a pair of photons entangled in three dimensions. Krenn’s naive expectation was that MELVIN would find configurations that combined these pairs of photons to create entangled states of at most nine dimensions. But “it actually found one solution, an extremely rare case, that has much higher entanglement than the rest of the states,” Krenn says.

    Eventually, he figured out that MELVIN had used a technique that multiple teams had developed nearly three decades ago. In 1991 one method was designed by Xin Yu Zou, Li Jun Wang and Leonard Mandel, all then at the University of Rochester (US). And in 1994 Zeilinger, then at the University of Innsbruck [Leopold-Franzens-Universität Innsbruck] (AT), and his colleagues came up with another. Conceptually, these experiments attempted something similar, but the configuration that Zeilinger and his colleagues devised is simpler to understand. It starts with one crystal that generates a pair of photons (A and B). The paths of these photons go right through another crystal, which can also generate two photons (C and D). The paths of photon A from the first crystal and of photon C from the second overlap exactly and lead to the same detector. If that detector clicks, it is impossible to tell whether the photon originated from the first or the second crystal. The same goes for photons B and D.

    A phase shifter is a device that effectively increases the path a photon travels as some fraction of its wavelength. If you were to introduce a phase shifter in one of the paths between the crystals and kept changing the amount of phase shift, you could cause constructive and destructive interference at the detectors. For example, each of the crystals could be generating, say, 1,000 pairs of photons per second. With constructive interference, the detectors would register 4,000 pairs of photons per second. And with destructive interference, they would detect none: the system as a whole would not create any photons even though individual crystals would be generating 1,000 pairs a second. “That is actually quite crazy, when you think about it,” Krenn says.

    MELVIN’s funky solution involved such overlapping paths. What had flummoxed Krenn was that the algorithm had only two crystals in its toolbox. And instead of using those crystals at the beginning of the experimental setup, it had wedged them inside an interferometer (a device that splits the path of, say, a photon into two and then recombines them). After much effort, he realized that the setup MELVIN had found was equivalent to one involving more than two crystals, each generating pairs of photons, such that their paths to the detectors overlapped. The configuration could be used to generate high-dimensional entangled states.

    Quantum physicist Nora Tischler, who was a Ph.D. student working with Zeilinger on an unrelated topic when MELVIN was being put through its paces, was paying attention to these developments. “It was kind of clear from the beginning [that such an] experiment wouldn’t exist if it hadn’t been discovered by an algorithm,” she says.

    Besides generating complex entangled states, the setup using more than two crystals with overlapping paths can be employed to perform a generalized form of Zeilinger’s 1994 quantum interference experiments with two crystals. Aephraim Steinberg, an experimentalist at the University of Toronto, who is a colleague of Krenn’s but has not worked on these projects, is impressed by what the AI found. “This is a generalization that (to my knowledge) no human dreamed up in the intervening decades and might never have done,” he says. “It’s a gorgeous first example of the kind of new explorations these thinking machines can take us on.”

    In one such generalized configuration with four crystals, each generating a pair of photons, and overlapping paths leading to four detectors, quantum interference can create situations where either all four detectors click (constructive interference) or none of them do so (destructive interference).

    But until recently, carrying out such an experiment remained a distant dream. Then, in a March preprint paper, a team led by Lan-Tian Feng of the University of Science and Technology [中国科学技术大学] (CN) at Chinese Academy of Sciences [中国科学院](CN) , in collaboration with Krenn, reported that they had fabricated the entire setup on a single photonic chip and performed the experiment. The researchers collected data for more than 16 hours: a feat made possible because of the photonic chip’s incredible optical stability, something that would have been impossible to achieve in a larger-scale tabletop experiment. For starters, the setup would require a square meter’s worth of optical elements precisely aligned on an optical bench, Steinberg says. Besides, “a single optical element jittering or drifting by a thousandth of the diameter of a human hair during those 16 hours could be enough to wash out the effect,” he says.

    During their early attempts to simplify and generalize what MELVIN had found, Krenn and his colleagues realized that the solution resembled abstract mathematical forms called graphs, which contain vertices and edges and are used to depict pairwise relations between objects. For these quantum experiments, every path a photon takes is represented by a vertex. And a crystal, for example, is represented by an edge connecting two vertices. MELVIN first produced such a graph and then performed a mathematical operation on it. The operation, called “perfect matching,” involves generating an equivalent graph in which each vertex is connected to only one edge. This process makes calculating the final quantum state much easier, although it is still hard for humans to understand.

    That changed with MELVIN’s successor THESEUS, which generates much simpler graphs by winnowing the first complex graph representing a solution that it finds down to the bare minimum number of edges and vertices (such that any further deletion destroys the setup’s ability to generate the desired quantum states). Such graphs are simpler than MELVIN’s perfect matching graphs, so it is even easier to make sense of any AI-generated solution.

    Renner is particularly impressed by THESEUS’s human-interpretable outputs. “The solution is designed in such a way that the number of connections in the graph is minimized,” he says. “And that’s naturally a solution we can better understand than if you had a very complex graph.”

    Eric Cavalcanti of Griffith University (AU) is both impressed by the work and circumspect about it. “These machine-learning techniques represent an interesting development. For a human scientist looking at the data and interpreting it, some of the solutions may look like ‘creative’ new solutions. But at this stage, these algorithms are still far from a level where it could be said that they are having truly new ideas or coming up with new concepts,” he says. “On the other hand, I do think that one day they will get there. So these are baby steps—but we have to start somewhere.”

    Steinberg agrees. “For now, they are just amazing tools,” he says. “And like all the best tools, they’re already enabling us to do some things we probably wouldn’t have done without them.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    Scientific American , the oldest continuously published magazine in the U.S., has been bringing its readers unique insights about developments in science and technology for more than 160 years.

     
  • richardmitnick 1:01 pm on June 9, 2021 Permalink | Reply
    Tags: "Early endeavours on the path to reliable quantum machine learning", Computer scientists led by ETH Zürich conduct an early exploration for reliable quantum machine learning., , Quantum Physics, , , The fact that quantum states can superpose and entangle creates a basis that allows quantum computers the access to a fundamentally richer set of processing logic., The future quantum computers should be capable of super-​fast and reliable computation. Today this is still a major challenge., Translating classical wisdom into the quantum realm.   

    From Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich] (CH): “Early endeavours on the path to reliable quantum machine learning” 

    From Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich] (CH)

    08.06.2021
    Florian Meyer

    The future quantum computers should be capable of super-​fast and reliable computation. Today, this is still a major challenge. Now, computer scientists led by ETH Zürich conduct an early exploration for reliable quantum machine learning.

    1
    Building on concepts such as quantum entanglement, quantum computers promise a wealth of machine learning applications. (Photo: Keystone/Science Photo Library)

    Anyone who collects mushrooms knows that it is better to keep the poisonous and the non-​poisonous ones apart. Not to mention what would happen if someone ate the poisonous ones. In such “classification problems”, which require us to distinguish certain objects from one another and to assign the objects we are looking for to certain classes by means of characteristics, computers can already provide useful support to humans.

    Intelligent machine learning methods can recognise patterns or objects and automatically pick them out of data sets. For example, they could pick out those pictures from a photo database that show non-​toxic mushrooms. Particularly with very large and complex data sets, machine learning can deliver valuable results that humans would not be able to find out, or only with much more time. However, for certain computational tasks, even the fastest computers available today reach their limits. This is where the great promise of quantum computers comes into play: that one day they will also perform super-​fast calculations that classical computers cannot solve in a useful period of time.

    The reason for this “quantum supremacy” lies in physics: quantum computers calculate and process information by exploiting certain states and interactions that occur within atoms or molecules or between elementary particles.

    The fact that quantum states can superpose and entangle creates a basis that allows quantum computers the access to a fundamentally richer set of processing logic. For instance, unlike classical computers, quantum computers do not calculate with binary codes or bits, which process information only as 0 or 1, but with quantum bits or qubits, which correspond to the quantum states of particles. The crucial difference is that qubits can realise not only one state – 0 or 1 – per computational step, but also a state in which both superpose. These more general manners of information processing in turn allow for a drastic computational speed-​up in certain problems.

    2
    A reliable quantum classification algorithm correctly classifies a toxic mushroom as “poisonous” while a noisy, perturbed one classifies it faultily as “edible”. (Image: npj Quantum Information / DS3Lab ETH Zürich.)

    Translating classical wisdom into the quantum realm.

    These speed advantages of quantum computing are also an opportunity for machine learning applications – after all, quantum computers could compute the huge amounts of data that machine learning methods need to improve the accuracy of their results much faster than classical computers.

    However, to really exploit the potential of quantum computing, one has to adapt the classical machine learning methods to the peculiarities of quantum computers. For example, the algorithms, i.e. the mathematical calculation rules that describe how a classical computer solves a certain problem, must be formulated differently for quantum computers. Developing well-​functioning “quantum algorithms” for machine learning is not entirely trivial, because there are still a few hurdles to overcome along the way.

    On the one hand, this is due to the quantum hardware. At ETH Zürich, researchers currently have quantum computers that work with up to 17 qubits (see “ETH Zürich and PSI found Quantum Computing Hub” of 3 May 2021). However, if quantum computers are to realise their full potential one day, they might need thousands to hundreds of thousands of qubits.

    Quantum noise and the inevitability of errors

    One challenge that quantum computers face concerns their vulnerability to error. Today’s quantum computers operate with a very high level of “noise”, as errors or disturbances are known in technical jargon. For the American Physical Society (US), this noise is “the major obstacle to scaling up quantum computers”. No comprehensive solution exists for both correcting and mitigating errors. No way has yet been found to produce error-​free quantum hardware, and quantum computers with 50 to 100 qubits are too small to implement correction software or algorithms.

    To a certain extent, one has to live with the fact that errors in quantum computing are in principle unavoidable, because the quantum states on which the concrete computational steps are based can only be distinguished and quantified with probabilities. What can be achieved, on the other hand, are procedures that limit the extent of noise and perturbations to such an extent that the calculations nevertheless deliver reliable results. Computer scientists refer to a reliably functioning calculation method as “robust” and in this context also speak of the necessary “error tolerance”.

    This is exactly what the research group led by Ce Zhang, ETH computer science professor and member of the ETH AI Center, has has recently explored, somehow “accidentally” during an endeavor to reason about the robustness of classical distributions for the purpose of building better machine learning systems and platforms. Together with Professor Nana Liu from Shanghai Jiao Tong University [海交通大学](CN) and with Professor Bo Li from the University of Illinois Urbana-Champaign(US), they have developed a new approach. This allows them to prove the robustness conditions of certain quantum-​based machine learning models, for which the quantum computation is guaranteed to be reliable and the result to be correct. The researchers have published their approach, which is one of the first of its kind, in the scientific journal npj Quantum Information.

    Protection against errors and hackers

    “When we realised that quantum algorithms, like classical algorithms, are prone to errors and perturbations, we asked ourselves how we can estimate these sources of errors and perturbations for certain machine learning tasks, and how we can guarantee the robustness and reliability of the chosen method,” says Zhikuan Zhao, a postdoc in Ce Zhang’s group. “If we know this, we can trust the computational results, even if they are noisy.”

    The researchers investigated this question using quantum classification algorithms as an example – after all, errors in classification tasks are tricky because they can affect the real world, for example if poisonous mushrooms were classified as non-​toxic. Perhaps most importantly, using the theory of quantum hypothesis testing – inspired by other researchers’ recent work in applying hypothesis testing in the classical setting – which allows quantum states to be distinguished, the ETH researchers determined a threshold above which the assignments of the quantum classification algorithm are guaranteed to be correct and its predictions robust.

    With their robustness method, the researchers can even verify whether the classification of an erroneous, noisy input yields the same result as a clean, noiseless input. From their findings, the researchers have also developed a protection scheme that can be used to specify the error tolerance of a computation, regardless of whether an error has a natural cause or is the result of manipulation from a hacking attack. Their robustness concept works for both hacking attacks and natural errors.

    “The method can also be applied to a broader class of quantum algorithms,” says Maurice Weber, a doctoral student with Ce Zhang and the first author of the publication. Since the impact of error in quantum computing increases as the system size rises, he and Zhao are now conducting research on this problem. “We are optimistic that our robustness conditions will prove useful, for example, in conjunction with quantum algorithms designed to better understand the electronic structure of molecules.”

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    ETH Zurich campus
    Swiss Federal Institute of Technology in Zürich [ETH Zürich] [Eidgenössische Technische Hochschule Zürich] (CH) is a public research university in the city of Zürich, Switzerland. Founded by the Swiss Federal Government in 1854 with the stated mission to educate engineers and scientists, the school focuses exclusively on science, technology, engineering and mathematics. Like its sister institution Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne](CH) , it is part of the Swiss Federal Institutes of Technology Domain (ETH Domain)) , part of the Swiss Federal Department of Economic Affairs, Education and Research.

    The university is an attractive destination for international students thanks to low tuition fees of 809 CHF per semester, PhD and graduate salaries that are amongst the world’s highest, and a world-class reputation in academia and industry. There are currently 22,200 students from over 120 countries, of which 4,180 are pursuing doctoral degrees. In the 2021 edition of the QS World University Rankings ETH Zürich is ranked 6th in the world and 8th by the Times Higher Education World Rankings 2020. In the 2020 QS World University Rankings by subject it is ranked 4th in the world for engineering and technology (2nd in Europe) and 1st for earth & marine science.

    As of November 2019, 21 Nobel laureates, 2 Fields Medalists, 2 Pritzker Prize winners, and 1 Turing Award winner have been affiliated with the Institute, including Albert Einstein. Other notable alumni include John von Neumann and Santiago Calatrava. It is a founding member of the IDEA League and the International Alliance of Research Universities (IARU) and a member of the CESAER network.

    ETH Zürich was founded on 7 February 1854 by the Swiss Confederation and began giving its first lectures on 16 October 1855 as a polytechnic institute (eidgenössische polytechnische Schule) at various sites throughout the city of Zurich. It was initially composed of six faculties: architecture, civil engineering, mechanical engineering, chemistry, forestry, and an integrated department for the fields of mathematics, natural sciences, literature, and social and political sciences.

    It is locally still known as Polytechnikum, or simply as Poly, derived from the original name eidgenössische polytechnische Schule, which translates to “federal polytechnic school”.

    ETH Zürich is a federal institute (i.e., under direct administration by the Swiss government), whereas the University of Zürich [Universität Zürich ] (CH) is a cantonal institution. The decision for a new federal university was heavily disputed at the time; the liberals pressed for a “federal university”, while the conservative forces wanted all universities to remain under cantonal control, worried that the liberals would gain more political power than they already had. In the beginning, both universities were co-located in the buildings of the University of Zürich.

    From 1905 to 1908, under the presidency of Jérôme Franel, the course program of ETH Zürich was restructured to that of a real university and ETH Zürich was granted the right to award doctorates. In 1909 the first doctorates were awarded. In 1911, it was given its current name, Eidgenössische Technische Hochschule. In 1924, another reorganization structured the university in 12 departments. However, it now has 16 departments.

    ETH Zürich, EPFL (Swiss Federal Institute of Technology in Lausanne) [École polytechnique fédérale de Lausanne](CH), and four associated research institutes form the Domain of the Swiss Federal Institutes of Technology (ETH Domain) [ETH-Bereich; Domaine des Écoles polytechniques fédérales] (CH) with the aim of collaborating on scientific projects.

    Reputation and ranking

    ETH Zürich is ranked among the top universities in the world. Typically, popular rankings place the institution as the best university in continental Europe and ETH Zürich is consistently ranked among the top 1-5 universities in Europe, and among the top 3-10 best universities of the world.

    Historically, ETH Zürich has achieved its reputation particularly in the fields of chemistry, mathematics and physics. There are 32 Nobel laureates who are associated with ETH Zürich, the most recent of whom is Richard F. Heck, awarded the Nobel Prize in chemistry in 2010. Albert Einstein is perhaps its most famous alumnus.

    In 2018, the QS World University Rankings placed ETH Zürich at 7th overall in the world. In 2015, ETH Zürich was ranked 5th in the world in Engineering, Science and Technology, just behind the Massachusetts Institute of Technology(US), Stanford University(US) and University of Cambridge(UK). In 2015, ETH Zürich also ranked 6th in the world in Natural Sciences, and in 2016 ranked 1st in the world for Earth & Marine Sciences for the second consecutive year.

    In 2016, Times Higher Education WorldUniversity Rankings ranked ETH Zürich 9th overall in the world and 8th in the world in the field of Engineering & Technology, just behind the Massachusetts Institute of Technology(US), Stanford University(US), California Institute of Technology(US), Princeton University(US), University of Cambridge(UK), Imperial College London(UK) and University of Oxford(UK).

    In a comparison of Swiss universities by swissUP Ranking and in rankings published by CHE comparing the universities of German-speaking countries, ETH Zürich traditionally is ranked first in natural sciences, computer science and engineering sciences.

    In the survey CHE ExcellenceRanking on the quality of Western European graduate school programs in the fields of biology, chemistry, physics and mathematics, ETH Zürich was assessed as one of the three institutions to have excellent programs in all the considered fields, the other two being Imperial College London(UK) and the University of Cambridge(UK), respectively.

     
  • richardmitnick 11:05 am on June 6, 2021 Permalink | Reply
    Tags: "Nuclear clocks could outdo atomic clocks as the most precise timepieces", , Atomic clocks tally time using the energy jumps of atoms’ electrons., , , Nuclear clocks would be a brand-new type of clock-one that would keep time based on the physics of atoms’ hearts., Physicists aim to build nuclear clocks., , Quantum Physics, , Today’s most precise clocks-called atomic clocks rely on the behavior of atoms’ electrons.   

    From Science News : Women in STEM-Adriana Pálffy; Marianna Safronova “Nuclear clocks could outdo atomic clocks as the most precise timepieces” 

    From Science News

    June 4, 2021
    Emily Conover

    But first, physicists need to figure out how to build them .

    1
    Physicists aim to build nuclear clocks, one depicted in this artist’s interpretation, which could keep time better than atomic clocks, the most precise clocks ever created. Credit: Vienna University of Technology (TU Wien) [Technische Universität Wien](AT).

    Nuclear clocks could be the GOAT: Greatest of all timepieces.

    If physicists can build them, nuclear clocks would be a brand-new type of clock-one that would keep time based on the physics of atoms’ hearts. Today’s most precise clocks, called atomic clocks, rely on the behavior of atoms’ electrons. But a clock based on atomic nuclei could reach 10 times the precision of those atomic clocks, researchers estimate.

    Better clocks could improve technologies that depend on them, such as GPS navigation, physicist Peter Thirolf said June 3 during an online meeting of the American Physical Society (US) Division of Atomic, Molecular and Optical Physics. But “it’s not just about timekeeping.” Unlike atoms’ electrons, atomic nuclei are subject to the strong nuclear force, which holds protons and neutrons together. “A nuclear clock sees a different part of the world,” said Thirolf, of Ludwig Maximilians University of Munich [Ludwig-Maximilians-Universität München](DE). That means nuclear clocks could allow new tests of fundamental ideas in physics, including whether supposedly immutable numbers in physics known as fundamental constants are, in fact, constant.

    Atomic clocks tally time using the energy jumps of atoms’ electrons. According to quantum physics, electrons in atoms can carry only certain amounts of energy, in specific energy levels. To bump electrons in an atom from one energy level to another, an atomic clock’s atoms must be hit with laser light of just the right frequency. That frequency — the rate of oscillation of the light’s electromagnetic waves — serves as a highly precise timekeeper.

    Like the electrons in an atom, the protons and neutrons within atomic nuclei also occupy discrete energy levels. Nuclear clocks would be based on jumps between those nuclear energy levels, rather than those of electrons. Notably, nuclei are resistant to the effects of stray electric or magnetic fields that can hinder atomic clocks. As a result, nuclear clocks “would be more stable and more accurate,” says theoretical physicist Adriana Pálffy of Friedrich–Alexander University Erlangen–Nürnberg [Friedrich-Alexander-Universität Erlangen-Nürnberg] (DE).

    But there’s a problem. To tally time with nuclei, scientists need to be able to set off the jump between nuclear energy levels with a laser. “Nuclear levels are not normally accessible with lasers,” said theoretical physicist Marianna Safronova of the University of Delaware (US) in a June 2 talk at the meeting. For most nuclei, that would require light of higher energy than suitable lasers can achieve. Luckily, there’s one lone exception in all of the known nuclei, Safronova said, “a freak-of-nature thing.” A variety of thorium called thorium-229 has a pair of energy levels close enough in energy that a laser could potentially set off the jump.

    Recent measurements have more precisely pinpointed the energy of that jump, a crucial step toward building a thorium nuclear clock. Thirolf and colleagues estimated the energy by measuring electrons emitted when the nucleus jumps between the two levels, as reported in Nature in 2019. And in a 2020 paper in Physical Review Letters, physicist Andreas Fleischmann and colleagues measured other energy jumps the thorium nucleus can make, subtracting them to deduce the energy of the nuclear clock jump.

    2
    An array of highly sensitive detectors (shown in a false-color scanning electron microscope image) measured the energy of light emitted when thorium-229 atoms jumped between energy levels. Those measurements allowed Andreas Fleischmann and colleagues to estimate the energy of the jump that physicists aim to use to make a nuclear clock. Credit: Matthäus Krantz.

    The teams agree that the jump is just over 8 electron volts in energy. That energy corresponds to ultraviolet light in a range for which setting off the jump with a laser is possible, but at the edge of scientists’ capabilities.

    Now that physicists know the size of the energy jump, they are aiming to trigger it with lasers. At the meeting, physicist Chuankun Zhang of the research institute JILA [Joint Institute for Laboratory Astrophysics] U Colorado/National Institute of Standards and Technology (US) in Boulder, Colo., reported efforts to use a frequency comb (SN: 10/5/18) — a method of creating an array of discrete frequencies of laser light — to initiate the jump and measure its energy even better. “If it’s a success, we can directly build a nuclear-based optical clock from that,” he said at the meeting. Thirolf’s team also is working with frequency combs, aiming for a working nuclear clock within the next five years.

    Meanwhile, Pálffy is looking into using what’s called an “electronic bridge.” Rather than using a laser to directly initiate an energy jump by the nucleus, the laser would first excite the electrons, which would then transfer energy to the nucleus, Pálffy reported at the meeting.

    Nuclear clocks could let researchers devise new tests to determine if fundamental constants of nature vary over time. For example, some studies have suggested that the fine-structure constant, a number that sets the strength of electromagnetic interactions, could change (SN: 11/2/16). “This nuclear clock is a perfect system to search for variation of fundamental constants,” Victor Flambaum of the University of New South Wales (AU) said at the meeting. The devices could also test a foundation of Einstein’s general theory of relativity called the equivalence principle (SN: 12/4/17). Or they could search for dark matter, elusive undetected particles that physicists believe account for most of the universe’s matter, which could tweak the ticking of the clock.

    The potential of nuclear clocks is so promising that for Fleischmann, of Ruprecht Karl University of Heidelberg [Ruprecht-Karls-Universität Heidelberg](DE), it took just an instant to settle on tackling the quandary of how scientists could build a nuclear clock, he says. It was “from the very first second clear that this is a question that one should work on.”

    See the full article here .


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  • richardmitnick 3:27 pm on May 27, 2021 Permalink | Reply
    Tags: An experiment in which a quantum system consisting of two coupled atoms behaves surprisingly stable under electron bombardment., Decoherence is one of the greatest enemies of the quantum physicist., , , Quantum Physics, Quantum systems are considered extremely fragile. Even the smallest interactions with the environment can result in the loss of sensitive quantum effects., , The discovery could have far-reaching consequences for the development of quantum computers.   

    From Jülich Research Centre [Forschungszentrum Jülichs] (FZJ)(DE) via EurekaAlert : “Astonishing quantum experiment in Science raises questions” 

    From Jülich Research Centre [Forschungszentrum Jülichs] (FZJ)(DE)

    via

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    EurekaAlert

    1
    Credit: Enrique Sahagún, Scixel.

    Quantum systems are considered extremely fragile. Even the smallest interactions with the environment can result in the loss of sensitive quantum effects. In the renowned journal Science, however, researchers from Delft University of Technology [Technische Universiteit Delft] (NL), RWTH AACHEN UNIVERSITY [Rheinisch-Westfaelische Technische Hochschule (DE) and Forschungszentrum Jülich now present an experiment in which a quantum system consisting of two coupled atoms behaves surprisingly stable under electron bombardment. The experiment provide an indication that special quantum states might be realised in a quantum computer more easily than previously thought.

    The so-called decoherence is one of the greatest enemies of the quantum physicist. Experts understand by this the decay of quantum states. This inevitably occurs when the system interacts with its environment. In the macroscopic world, this exchange is unavoidable, which is why quantum effects rarely occur in daily life. The quantum systems used in research, such as individual atoms, electrons or photons, are better shielded, but are fundamentally similarly sensitive.

    “Systems subject to quantum physics, unlike classical objects, are not sharply defined in all their properties. Instead, they can occupy several states at once. This is called superposition,” Markus Ternes explains. “A famous example is Schrödinger’s thought experiment with the cat, which is temporarily dead and alive at the same time. However, the superposition breaks down as soon as the system is disturbed or measured. What is left then is only a single state, which is the measured value,” says the quantum physicist from Forschungszentrum Jülich and RWTH Aachen University.

    Given this context, the experiment that researchers at TU Delft have now carried out seems all the more astonishing. Using a new method, they succeeded for the first time in real-time observing how two coupled atoms freely exchange quantum information, switching back and forth between different states in a flip-flop interaction.

    “Each atom carries a small magnetic moment called spin. These spins influence each other, like compass needles do when you bring them close. If you give one of them a push, they will start moving together in a very specific way,” explains Sander Otte, head of the Delft team that performed the experiment.

    On a large scale, this kind of information exchange between atoms can lead to fascinating phenomena. Various forms of quantum technologies are based on these. A classical example is superconductivity: the effect where some materials lose all electrical resistivity below a critical temperature.

    Unconventional approach

    To observe this interaction between atoms, Otte and his team chose a rather direct way: Using a scanning tunnelling microscope, they placed two titanium atoms next to each other at a distance of just over one nanometre – one millionth of a millimetre. At that distance, the atoms are just able to feel each other’s spin. If you would now twist one of the two spins, the conversation will start by itself.

    Usually, this twist is performed by sending very precise radio signals to the atoms. This so-called spin resonance technique – which is quite reminiscent of the working principle of an MRI scanner found in hospitals – is used successfully in research on quantum bits. Among other things, quantum bits in certain types of quantum computers are programmed in such a way. However, the method has a disadvantage. “It is simply too slow,” says PhD student Lukas Veldman, lead author on the Science publication. “You have barely started twisting the one spin before the other starts to rotate along. This way you can never investigate what happens upon placing the two spins in opposite directions.”

    So the researchers tried something unorthodox: they rapidly inverted the spin of one of the two atoms with a sudden burst of electric current. To their surprise, this drastic approach resulted in a beautiful quantum interaction, exactly by the book. During the pulse, electrons collide with the atom, causing its spin to rotate. Otte: “But we always assumed that during this process, the delicate quantum information – the so-called coherence – was lost. After all, the electrons that you send are incoherent: the history of each electron prior to the collision is slightly different and this chaos is transferred to the atom’s spin, destroying any coherence.”

    The fact that this now seems not to be true was cause for some debate. Apparently, each random electron, regardless of its past, can initiate a superposition: a specific combination of elementary quantum states which is fully known and which forms the basis for almost any form of quantum technology. The aspect that these electrons are still connected to their environment via their history is obviously irrelevant. What is at stake here, then, is the violation of a principle of quantum physics, according to which every measurement irretrievably destroys the superposition of quantum states.

    “The crux is that it depends on the perspective,” argues Markus Ternes, co-author of the Science paper. “The electron inverts the spin of one atom causing it to point, say, to the left. You could view this as a measurement, erasing all quantum memory. But from the point of view of the combined system comprising both atoms, the resulting situation is not so mundane at all. For the two atoms together, the new state constitutes a perfect superposition, enabling the exchange of information between them. Crucially for this to happen is that both spins become entangled: a particular quantum state in which they share more information about each other than classically possible.”

    The discovery could have far-reaching consequences for the development of quantum computers, whose function is based on the entanglement and superposition of quantum states. If one follows the findings, one could get away with being slightly less careful when initializing quantum states than previously thought. For Otte and his team at TU Delft, however, the result is above all the starting point of further exciting experiments. Veldman: “Here we used two atoms, but what happens if you use three? Or ten, or a thousand? Nobody can predict that, because the computing power [for simulating such] numbers is not sufficient.”

    See the full article here.

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    Jülich Research Centre[Forschungszentrum Jülich] is a member of the Helmholtz Association of German Research Centres [Helmholtz-Gemeinschaft Deutscher Forschungszentren ](DE) and is one of the largest interdisciplinary research centres in Europe. It was founded on 11 December 1956 by the state of North Rhine-Westphalia as a registered association, before it became “Kernforschungsanlage Jülich GmbH” or Nuclear Research Centre Jülich in 1967. In 1990, the name of the association was changed to “Forschungszentrum Jülich GmbH”. It has close collaborations with RWTH Aachen in the form of Jülich-Aachen Research Alliance (JARA).

    Jülich Research Centre [Forschungszentrum Jülichs](FZJ)(DE) is situated in the middle of the Stetternich Forest in Jülich (Kreis Düren, Rheinland) and covers an area of 2.2 square kilometres.

    Jülich Research Centre [Forschungszentrum Jülichs](FZJ)(DE) employs more than 5,700 members of staff (2015) and works within the framework of the disciplines physics, chemistry, biology, medicine and engineering on the basic principles and applications in the areas of health, information, environment and energy. Amongst the members of staff, there are approx. 1,500 scientists including 400 PhD students and 130 diploma students. Around 600 people work in the administration and service areas, 500 work for project management agencies, and there are 1,600 technical staff members, while around 330 trainees are completing their training in more than 20 professions.

    More than 800 visiting scientists come to Forschungszentrum Jülich every year from about 50 countries.

     
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