From The Swiss Federal Institute of Technology in Lausanne [EPFL-École Polytechnique Fédérale de Lausanne] (CH): “Stabilizing polarons opens up new physics”

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

10.7.22
Papageorgiou

Physicists at EPFL have developed a formulation to solve the longstanding problem of electron self-interaction when studying polarons – quasiparticles produced by electron-phonon interactions in materials. The work can lead to unprecedented calculations of polarons in large systems, systematic studies of large sets of materials, and molecular dynamics evolving over long time periods.

One of the many peculiarities of quantum mechanics is that particles can also be described as waves. A common example is the photon, the particle associated with light.

In ordered structures, known as crystals, electrons can be seen and described as waves that spread across the entire system – a rather harmonious picture. As electrons move through the crystal, ions – atoms carrying a negative or positive charge — are periodically arranged in space.

Now, if we were to add an extra electron to the crystal, its negative charge could make the ions around it move away from their equilibrium positions. The electron charge would localize in space and couple to the surrounding structural – “lattice” – distortions of the crystal, giving rise to a new particle known as a polaron.

“Technically, a polaron is a quasi-particle, made up of an electron “dressed” by its self-induced phonons, which represent the quantized vibrations of the crystal,” says Stefano Falletta at EPFL’s School of Basic Sciences. He continues: “The stability of polarons arises from a competition between two energy contributions: the gain due to charge localization, and the cost due to lattice distortions. When the polaron destabilizes, the extra electron delocalizes over the entire system, while the ions restore their equilibrium positions.”

A polaron forming in magnesium oxide atoms. Credit: S. Falletta (EPFL)

Working with Professor Alfredo Pasquarello at EPFL, they have published two papers in Physical Review Letters [below] and Physical Review B [below] describing a new approach for solving a major shortcoming of a well-established theory that physicists use to study the interactions of electrons in materials. The method is called density functional theory or DFT, and is used in physics, chemistry, and materials science to study the electronic structure of many-body systems like atoms and molecules.

DFT is a powerful tool for performing ab-initio calculations of materials, by simplified treatment of the electron interactions. However, DFT is susceptible to spurious interactions of the electron with its own self – what physicists refer to as the “self-interaction problem”. This self-interaction is one of the greatest limitations of DFT, often leading to incorrect description of polarons, which are often destabilized.

“In our work, we introduce a theoretical formulation for the electron self-interaction that solves the problem of polaron localization in density functional theory,” says Falletta. “This gives access to accurate polaron stabilities within a computationally-efficient scheme. Our study paves the way to unprecedented calculations of polarons in large systems, in systematic studies involving large sets of materials, or in molecular dynamics evolving over long time periods.”

Science papers:
Physical Review Letters
Physical Review B

See the full article here .

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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.

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.

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 were located at Rue du Valentin in Lausanne. In 1869, it became the technical department of the public Académie de Lausanne. When the Académie was reorganized 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 organized into eight schools, themselves formed of institutes that group research units (laboratories or chairs) around common themes:

School of Basic Sciences
Institute of Mathematics
Institute of Chemical Sciences and Engineering
Institute of Physics
European Centre of Atomic and Molecular Computations
Bernoulli Center
Biomedical Imaging Research Center
Interdisciplinary Center for Electron Microscopy
MPG-EPFL Centre for Molecular Nanosciences and Technology
Swiss Plasma Center
Laboratory of Astrophysics

School of Engineering

Institute of Electrical Engineering
Institute of Mechanical Engineering
Institute of Materials
Institute of Microengineering
Institute of Bioengineering

School of Architecture, Civil and Environmental Engineering

Institute of Architecture
Civil Engineering Institute
Institute of Urban and Regional Sciences
Environmental Engineering Institute

School of Computer and Communication Sciences

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

Bachelor-Master Teaching Section in Life Sciences and Technologies
Brain Mind Institute
Institute of Bioengineering
Swiss Institute for Experimental Cancer Research
Global Health Institute
Ten Technology Platforms & Core Facilities (PTECH)
Center for Phenogenomics
NCCR Synaptic Bases of Mental Diseases

College of Management of Technology

Swiss Finance Institute at EPFL
Section of Management of Technology and Entrepreneurship
Institute of Technology and Public Policy
Institute of Management of Technology and Entrepreneurship
Section of Financial Engineering

College of Humanities

Human and social sciences teaching program

EPFL Middle East

Section of Energy Management and Sustainability

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

From The DOE’s Lawrence Berkeley National Laboratory: “Boron Nitride with a Twist Could Lead to New Way to Make Qubits”

From The DOE’s Lawrence Berkeley National Laboratory

10.6.22
Rachel Berkowitz

Easy control over bright emissions from the crystalline material offer a route toward scalable quantum computing and sensing.

Shaul Aloni, Cong Su, Alex Zettl, and Steven Louie at the Molecular Foundry. The researchers synthesized a device made from twisted layers of hexagonal boron nitride with color centers that can be switched on and off with a simple switch. (Credit: Marilyn Sargent/Berkeley Lab)

Achieving scalability in quantum processors, sensors, and networks requires novel devices that are easily manipulated between two quantum states. A team led by researchers from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) has now developed a method, using a solid-state “twisted” crystalline layered material, which gives rise to tiny light-emitting points called color centers. These color centers can be switched on and off with the simple application of an external voltage.

“This is a first step toward a color center device that engineers could build or adapt into real quantum systems,” said Shaul Aloni, a staff scientist at Berkeley Lab’s Molecular Foundry [below], who co-led the study. The work is detailed in the journal Nature Materials [below].

For example, the research could lead to a new way to make quantum bits, or qubits, which encode information in quantum computers.

Color centers are microscopic defects in a crystal, such as diamond, that usually emit bright and stable light of specific color when struck with laser or other energy source such as an electron beam. Their integration with waveguides, devices that guide light, can connect operations across a quantum processor. Several years ago researchers discovered that color centers in a synthesized material called hexagonal boron nitride (hBN), which is commonly used as a lubricant or additive for paints and cosmetics, emitted even brighter colors than color centers in diamond. But engineers have struggled to use the material in applications because producing the defects at a determined location is difficult, and they lacked a reliable way to switch the color centers on and off.

The Berkeley Lab team now solves these problems. Cong Su, a postdoc from the research group led by Alex Zettl, a faculty senior scientist at Berkeley Lab and professor of physics at UC Berkeley, examined how color centers behaved in different sophisticated forms of hBN. The researchers found that two stacked and twisted layers of the material resulted in the activation and enhancement of ultraviolet (UV) emission from a color center, which can be shut off when a voltage is applied across the structure. “It’s like a sandwich with two pieces of bread, but one rotated relative to the other,” said Zettl. The rotation between the two layers activates the color centers at the interface to become extremely bright. The applied voltage then easily and reversibly tunes the intensity from bright to completely dark, without “unrotating” the halves.

An electron beam placed at a series of locations on a sheet of twisted hBN intensifies the light emission from each location. The brightness depends on how long the beam sits at a given point, or the electron flux delivered to that point. The result is an illuminated pattern. (Credit: Su et al. 2022)

Aloni’s development of a modified electron microscope that not only probed the material’s structure but also collected the emitted light for analysis turned out to be key for this study. The setup uses an electron beam to excite the color centers; the researchers also found that they could use the electron beam to activate color centers and draw patterns, such as a smiley face, onto hBN. “People typically zap the material with lasers or ions, but we’ve instead zapped it with a beam of electrons,” said Zettl.

The study achieves three steps toward realization of a scalable quantum device. First, the UV color centers in hBN can be reliably activated to exceptional maximum brightness, by twisting the crystal interface. Second, these color centers can then be gradually and reversibly dimmed by a simple applied voltage. Finally, electron beam treatment allows further precise spatial positioning of these color centers.

Theoretical calculations led by Steven Louie, a faculty senior scientist at Berkeley Lab and distinguished professor of physics at UC Berkeley, provided candidates for the UV color center atomic configuration to help explain why their brightness depended on the twist angle. The light emission process involves an excited electron wandering around and recombining with a hole at the color center. But a typical hBN structure has many traps that could capture the electrons, preventing light emission. “Twisting the crystal layers removes many of these traps, or ‘quantum parking lots,’ near the interface,” said Louie.

The team next intends to prepare samples that allow atomic characterization to pinpoint the specific atomic structures behind this mechanism and add additional levels of control. “The work is pointing us in the direction of new types of mechanisms that we can use to control the emission even better, and this is very important for many applications in quantum information sciences,” said Aloni.

Science paper:
Nature Materials

See the full article here .

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LBNL campus

Bringing Science Solutions to the World

In the world of science, The Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the The National Academy of Sciences, 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 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 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 University of California- 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 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.

E.O. Lawrence’ first cyclotron.

LBNL 88 inch cyclotron.

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 The DOE’s Los Alamos Laboratory, and Robert Wilson founded The DOE’s Fermi National Accelerator Laboratory.

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 The Department of Energy . 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 DOE’s Lawrence Livermore National Laboratory) 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 , with management from the University of California. 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:

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.

The DOE’s Lawrence Berkeley National Laboratory Advanced Light Source.
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.

Berkeley Lab Laser Accelerator (BELLA) Center

A view of BELLA, the Berkeley Lab Laser Accelerator. Credit: Roy Kaltschmidt-Berkeley Lab.

The DOE Joint Genome Institute 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, DOE’s Oak Ridge National Laboratory (ORNL), DOE’s Pacific Northwest National Laboratory (PNNL), and the HudsonAlpha Institute for Biotechnology . 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.

LBNL Molecular Foundry

The LBNL Molecular Foundry 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 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 at Lawrence Berkeley National Laboratory.

Cray Cori II supercomputer at National Energy Research Scientific Computing Center at DOE’s Lawrence Berkeley National Laboratory, named after Gerty Cori, the first American woman to win a Nobel Prize in science.

NERSC Hopper Cray XE6 supercomputer.

NERSC Cray XC30 Edison supercomputer.

NERSC GPFS for Life Sciences.

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.

NERSC PDSF computer cluster in 2003.

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.

Cray Shasta Perlmutter SC18 AMD Epyc Nvidia pre-exascale supercomputer.

NERSC is a DOE Office of Science User Facility.

The DOE’s Energy Science Network 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 (JBEI), located in Emeryville, California. Other partners are the DOE’s Sandia National Laboratory, the University of California (UC) campuses of Berkeley and Davis, the Carnegie Institution for Science , and DOE’s Lawrence Livermore National Laboratory (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 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 leads JCESR and Berkeley Lab is a major partner.

From The Kiel University [Christian-Albrechts-Universität zu Kiel] (DE) And The University of Hamburg [Universität Hamburg] (DE): “Magnetic nano mosaics”

From The Kiel University [Christian-Albrechts-Universität zu Kiel] (DE)

And

The University of Hamburg [Universität Hamburg] (DE)

10.5.22

PD Dr. Kirsten von Bergmann
Institute for Nanostructure and Solid State Physics
University of Hamburg
040 / 42838-6295
kirsten.von.bergmann@physik.uni-hamburg.de

Professor Dr. Stefan Heinze
Institute of Theoretical Physics and Astrophysics
Kiel University
0431 / 880-4127
heinze@theo-physik.uni-kiel.de

Press Contact:
Julia Siekmann
Science Communication Officer
Research area Kiel Nano Surface and Interface Sciences
jsiekmann@uv.uni-kiel.de
+49 (0)431/880-4855

Physics team from the universities of Kiel and Hamburg discovers new class of magnetic lattices.

The image shows the different orientation of atomic “bar magnets” of an iron film: In a magnetic mosaic lattice (above), they are oriented in groups either upwards (purple) or downwards (white). In the skyrmion lattice (below), on the other hand, they point in all directions. © André Kubetzka.

A measurement using spin-polarised scanning tunnelling microscopy (SP-STM) makes the hexagonal arrangement in the magnetic mosaic lattice visible on the nanometre scale. Due to a twist of the mosaic lattice on the atomic lattice, two rotational domains appear which deviate from each other by about 13° (see markings and graphs on the right). © André Kubetzka.

For about ten years, magnetic skyrmions – particle-like, stable magnetic whirls that can form in certain materials and possess fascinating properties – have been a focus of research: electrically easily controlled and only a few nanometers in size, they are suitable for future applications in spin electronics, quantum computers or neuromorphic chips. These magnetic whirls were first found in regular lattices, so-called “skyrmion lattices”, and later individual skyrmions were also observed at the University of Hamburg. Researchers from Kiel University and the University of Hamburg have now discovered a new class of spontaneously occurring magnetic lattices. They are related to skyrmion lattices, but their “atomic bar magnets” on the nanometer scale are oriented differently. A fundamental understanding of how such complex spin structures form, how they are arranged and remain stable is also needed for future applications. The results are published in the current issue of Nature Communications [below].

Quantum mechanical interactions

Attaching magnets to a refrigerator or reading data from a hard drive is only possible because of a quantum mechanical exchange interaction between the atomic bar magnets on the microscopic scale. This interaction, discovered by Werner Heisenberg in 1926, explains not only the parallel alignment of atomic bar magnets in ferromagnets, but also the occurrence of other magnetic configurations, such as antiferromagnets. Today many other magnetic interactions are known, which has led to a variety of possible magnetic states and new research questions. This is also important for skyrmion lattices. Here the atomic bar magnets show in all spatial directions, which is only possible due to the competition of different interactions.

“In our measurements, we found a hexagonal arrangement of magnetic contrasts, and at first we thought that was also a skyrmion lattice. Only later did it become clear that it could be a nanoscale magnetic mosaic,” says PD Dr. Kirsten von Bergmann. With her team from the University of Hamburg, she experimentally studied thin metallic films of iron and rhodium using spin-polarized scanning tunneling microscopy. This allows magnetic structures to be imaged down to the atomic scale. The observed magnetic lattices occurred spontaneously as in a ferromagnet, i.e., without an applied magnetic field. “With a magnetic field, we can invert the mosaic lattices, because the opposing spins only partially compensate for each other,” explains Dr. André Kubetzka, also from the University of Hamburg.

Surprising: Magnetically different alignment

Based on these measurements, the group of Prof. Dr. Stefan Heinze (Kiel University) performed quantum mechanical calculations on the supercomputers of the North German High Performance Computing Network (HLRN). They show that in the investigated iron films the tilting of the atomic bar magnets in a lattice of magnetic vortices, i.e. in all spatial directions, is very unfavorable. Instead, a nearly parallel or antiparallel alignment of neighboring atomic bar magnets is favored.

“This result completely surprised us. A lattice of skyrmions was thus no longer an option to explain the experimental observations,” says Mara Gutzeit, doctoral researcher and first author of the study. The development of an atomistic spin model made clear that it must be a novel class of magnetic lattices, which the researchers called “mosaic lattices”. “We found out that these mosaic-like magnetic structures are caused by higher-order exchange terms, predicted only a few years ago,” says Dr. Soumyajyoti Haldar from the group of Kiel.

“The study impressively shows how diverse spin structures can be and that a close collaboration between experimentally and theoretically working research groups can be really helpful for their understanding. In this field a few more surprises can be expected in the future,” states Professor Stefan Heinze.

Science paper:
Nature Communications
See the science paper for instructive images.
_________________________________________________
About spin electronics:

In addition to the charge of the electrons, spin electronics also uses their so-called spin. This electron spin is a quantum mechanical property and can be understood in simplified terms as the rotation of the electrons around their own axis. This is linked to a magnetic moment that leads to the formation of “atomic bar magnets” (atomic spins) in magnetic materials. They are suitable for processing and storing information. Through targeted electrical manipulation, it would be possible to create faster, more energy-saving and more powerful components for information technology.

See the full article here .

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The University of Hamburg [Universität Hamburg] (DE) is the largest institution for research and education in northern Germany. As one of the country’s largest universities, we offer a diverse range of degree programs and excellent research opportunities. The University boasts numerous interdisciplinary projects in a broad range of fields and an extensive partner network of leading regional, national, and international higher education and research institutions.
Sustainable science and scholarship

Universität Hamburg is committed to sustainability. All our faculties have taken great strides towards sustainability in both research and teaching.
Excellent research

As part of the Excellence Strategy of the Federal and State Governments, Universität Hamburg has been granted clusters of excellence for 4 core research areas: Advanced Imaging of Matter (photon and nanosciences), Climate, Climatic Change, and Society (CliCCS) (climate research), Understanding Written Artefacts (manuscript research) and Quantum Universe (mathematics, particle physics, astrophysics, and cosmology).

An equally important core research area is Infection Research, in which researchers investigate the structure, dynamics, and mechanisms of infection processes to promote the development of new treatment methods and therapies.
Outstanding variety: over 170 degree programs

Universität Hamburg offers approximately 170 degree programs within its eight faculties:

Faculty of Law
Faculty of Business, Economics and Social Sciences
Faculty of Medicine
Faculty of Education
Faculty of Mathematics, Informatics and Natural Sciences
Faculty of Psychology and Human Movement Science
Faculty of Business Administration (Hamburg Business School).

Universität Hamburg is also home to several museums and collections, such as the Zoological Museum, the Herbarium Hamburgense, the Geological-Paleontological Museum, the Loki Schmidt Garden, and the Hamburg Observatory.
History

Universität Hamburg was founded in 1919 by local citizens. Important founding figures include Senator Werner von Melle and the merchant Edmund Siemers. Nobel Prize winners such as the physicists Otto Stern, Wolfgang Pauli, and Isidor Rabi taught and researched at the University. Many other distinguished scholars, such as Ernst Cassirer, Erwin Panofsky, Aby Warburg, William Stern, Agathe Lasch, Magdalene Schoch, Emil Artin, Ralf Dahrendorf, and Carl Friedrich von Weizsäcker, also worked here.

The Kiel University [ Christian-Albrechts-Universität zu Kiel ] (DE) was founded back in 1665. It is Schleswig-Holstein’s oldest, largest and best-known university, with over 26,000 students and around 3,000 members of staff. It is also the only fully-fledged university in the state. Seven Nobel prize winners have worked here. The CAU has been successfully taking part in the Excellence Initiative since 2006. The Cluster of Excellence The Future Ocean, which was established in cooperation with the GEOMAR [Helmholtz-Zentrum für Ozeanforschung Kiel](DE) in 2006, is internationally recognized. The second Cluster of Excellence “Inflammation at Interfaces” deals with chronic inflammatory diseases. The Kiel Institute for the World Economy is also affiliated with Kiel University. The university has a great reputation for its focus on public international law. The oldest public international law institution in Germany and Europe – the Walther Schuecking Institute for International Law – is based in Kiel.

History

The University of Kiel was founded under the name Christiana Albertina on 5 October 1665 by Christian Albert, Duke of Holstein-Gottorp. The citizens of the city of Kiel were initially quite sceptical about the upcoming influx of students, thinking that these could be “quite a pest with their gluttony, heavy drinking and their questionable character” (German: mit Fressen, Sauffen und allerley leichtfertigem Wesen sehr ärgerlich seyn). But those in the city who envisioned economic advantages of a university in the city won, and Kiel thus became the northernmost university in the German Holy Roman Empire.

After 1773, when Kiel had come under Danish rule, the university began to thrive, and when Kiel became part of Prussia in the year 1867, the university grew rapidly in size. The university opened one of the first botanical gardens in Germany (now the Alter Botanischer Garten Kiel), and Martin Gropius designed many of the new buildings needed to teach the growing number of students.

The Christiana Albertina was one of the first German universities to obey the Gleichschaltung in 1933 and agreed to remove many professors and students from the school, for instance Ferdinand Tönnies or Felix Jacoby. During World War II, the University of Kiel suffered heavy damage, therefore it was later rebuilt at a different location with only a few of the older buildings housing the medical school.

In 2019, it was announced it has banned full-face coverings in classrooms, citing the need for open communication that includes facial expressions and gestures.

Faculties

Faculty of Theology
Faculty of Law
Faculty of Business, Economics and Social Sciences
Faculty of Medicine
Faculty of Arts and Humanities
Faculty of Mathematics and Natural Sciences
Faculty of Agricultural Science and Nutrition
Faculty of Engineering

From “ars technica“: “Black holes can’t trash info about what they swallow—and that’s a problem”

From “ars technica“

10.3.22
Paul Sutter

Solving the information paradox could unlock quantum gravity and unification of forces.

Aaron Horowitz/Getty Images.

Three numbers.

Just three numbers—that’s all it takes to completely, unequivocally, 100 percent describe a black hole in general relativity. If I tell you the mass and electric charge and spin (i.e. angular momentum) of a black hole we’re done. That’s all we’ll ever know about it and all we’ll ever need to describe its features.

Those three numbers allow us to calculate everything about how a black hole will interact with its environment, how objects around it will respond to it, and how the black hole will evolve in the future.

For all their ferocious gravitational abilities and their unholy exotic natures, black holes are surprisingly simple. If I give you two black holes with the exact same mass, charge, and spin, you wouldn’t be able to tell them apart. If I swapped their places without you looking, you wouldn’t know that I did it.

This also means that when you see a fully formed black hole, you have no idea what made it. Any combination of mass squeezed into a sufficiently small volume could have done the job. It could have been the ultra-dense core of a dying star. It could have been an extremely dense litter of adorable kittens squashed into oblivion.

As long as the mass, charge, and spin are the same, the history is irrelevant. No information about the original material that created the black hole survives. Or does it?

Founding charters

“Information” is a bit of a loaded term; it can take on various definitions depending on who you ask and what mood they’re in. In physics, the concept of information is tightly linked to our understanding of how physical systems evolve and how we construct our theories of physics.

We like to think that physics is a relatively useful paradigm for understanding the Universe we live in. One of the ways that physics is useful is its power of prediction. If I give you a list of all the information about a system, I should be able to apply my laws and theories of physics to tell you how that system will evolve. The reverse is also true. If I tell you the state of a system now, you can run all the math backward to figure out how the system got to its present state.

These two concepts are known as determinism (I can predict the future) and reversibility (I can read the past) and are pretty much the foundational core of physics. If our theories of physics didn’t have these properties, we wouldn’t be able to get much work done.

These two concepts also apply to quantum mechanics. Yes, quantum mechanics puts strict limits on what we can measure about the Universe, but that doesn’t mean all bets are off. Instead, we can simply replace a sharply defined classical state with a fuzzier quantum state and move on with our lives; the quantum state evolves according to the Schrödinger equation, which upholds both determinism and reversibility, so we’re all good.

This one-two punch of determinism and reversibility means that, in terms of physics, information must be preserved during any process. It can’t be either created or destroyed—if we were to add or remove information willy-nilly, we wouldn’t be able to predict the future or read the past. Any loss or gain means there would either be missing information or extra information, so all of physics would crumble to dust.

There are many processes that appear to destroy information, but that’s only because we’re not keeping careful enough track. Take, for example, the burning of a book. If I gave you a pile of ashes, this would appear to be irreversible: There’s no way you could put the book back together. But if you have a sufficiently powerful microscope at your disposal (and a lot of patience) and got to watch me in the act of burning the book, you could—in principle at least, which is good enough—watch and track the motion of every single molecule in the process. You could then reverse all those motions and all those interactions to reconstruct the book. Information is not lost when you burn a book; it’s merely scrambled.

In the traditional, classical view of black holes, all this business about information is not a problem at all. The information that went into building the black hole is simply locked away behind the event horizon—the one-way boundary at the black hole’s surface that makes it so unique. Once there, the information will never be seen in this Universe again. Whether the black hole was formed from dying stars or squashed kittens, it doesn’t practically matter. The information may not be destroyed, but it’s permanently hidden from our prying eyes.

Hawking’s surprise

At least, that’s what we thought until the mid-1970s, when famed astrophysicist Stephen Hawking discovered that black holes aren’t entirely… well, black.

Hawking was exploring the nature of quantum fields near the event horizons of black holes when he discovered an unusual property. The interaction of the event horizon with the quantum fields triggered the emission of radiation; light and particles could escape from the otherwise inescapable event horizons, causing the black holes to lose mass and eventually evaporate.

Curiously, Hawking found that the radiation emitted by a black hole was perfectly thermal, meaning that it contained no information whatsoever except for that regarding the mass, charge, and spin of the black hole. Thus was born the black hole information paradox. Unlike if it were burned, were a book to fall into a black hole, there’s no way we could reconstruct the words from the radiation that came out. After the black hole radiated away all its mass and disappeared in a poof of particles, all the information about all the objects (books, stars, kittens, etc.) that fell in to create the black hole would disappear along with it.

But as we went over earlier, information can’t just disappear, so this was a bit of a puzzle.

The problem languished for decades, with physicists arguing back and forth (and even changing their minds!) about how to fix it. Hawking’s calculations could be wrong, but that would mean we were missing something important about the nature of quantum field theory—which was well-tested. Or our understanding of gravity could be wrong, although that was well-tested, too. Or we needed to give up our cherished notions of the conservation of information… which was also well-tested.

It won’t be spoiling the rest of this article to tell you that we still do not have a solution to the paradox. But in studying this troubling problem, physicists have come up with several interesting clues that are helping us move in what’s hopefully the right direction.

Information wants to be free

The first major clue came in the late 1990s when theoretical physicist Juan Maldacena calculated the entropy of a black hole. In a nutshell, this calculation of the entropy was a count of all the missing information that gets locked behind an event horizon. He found that the amount of entropy inside a black hole is proportional to the radius squared—and thus proportional to the surface area of the black hole. (That’s in contrast to the radius cubed, which is proportional to the volume.)

For example, if you take a standard black hole and add one single bit of information to it (as encoded by, say, a single photon with a wavelength equal to the radius of the black hole) its surface area will increase by exactly the square of the Planck length.

Leading from Hawking’s insight, this result suggested that the most important property of a black hole—the place where we should focus our attention and efforts—was not the infinitely dense singularity in the center but the surface of the event horizon, which separates the insides of a black hole from the Universe outside.

The relationship between a black hole’s surface and its entropy also dovetailed nicely with another concept evolving out of the string theory community at the time, something known as the “holographic principle.”

String theory is an attempt to develop a theory of everything, a complete description of all the forces of nature under a single unifying framework. That attempt hasn’t seen a lot of success because nobody has been able to use string theory to develop a quantum theory of gravity—all the math just gets too complex to solve. So several physicists in the ’90s wondered if there was a way to simplify the problem. Instead of trying to work through the nasty problem of quantum gravity in our normal four-dimensional Universe, maybe we could encode all the information contained in the Universe onto an imaginary three-dimensional boundary and get an easier version of the math.

Maldacena was able to provide a realization of that idea via what’s called the AdS/CFT correspondence. It works like this. You start by trying to solve a problem involving quantum gravity in a particular kind of Universe called anti-de Sitter space (AdS, which has no matter or radiation inside it but does have positive cosmological constant). Mathematically, you can project all the information in that Universe onto its surface. Once you make that transformation, your impossible-to-solve quantum gravity problem turns into a merely very-difficult-to-solve problem in conformal field theory (that’s the CFT part), which is a kind of quantum field theory that doesn’t include gravity at all. You can then solve your problem and translate the solution back into the full-dimensional Universe and move on with your life.

This correspondence between the information within a volume and the information present on that volume’s surface is the holographic principle (named so because holograms store 3D information on a 2D surface). The correspondence has yet to be proven mathematically, but it has turned out to be useful for solving various kinds of specialized problems in the realm of high-energy physics.

What does this have to do with black holes? The fact that a black hole’s information content is related directly to its surface and not its volume seems to be a major clue that the resolution to the paradox may come from using the AdS/CFT correspondence, which recasts problems involving extended objects with gravity into surface-layer problems without gravity. Leaving aside the slightly uncomfortable fact that the inside of a black hole is definitely not an anti-de Sitter space, perhaps the black holes are trying to tell us something fundamental not just about the nature of gravity but about reality itself.

It was based on this correspondence that Hawking declared a winner in the love-it-or-leave-it debate regarding the preservation of information. Based on the AdS/CFT holographic picture of the Universe, information must be preserved (somehow) on the surface of a black hole and end up leaving the black hole (somehow) via Hawking radiation. If you threw a book into a black hole and kept careful track of the particles emitted over the next few trillions of years, you should be able to put the book back together again.

Somehow.

The “promised land” of quantum gravity

The “how” part of this story has been keeping some physicists up late at night for the past 20 years. One particular line of thinking has been to closely examine the nature of spacetime near the event horizon. In Hawking’s original approach, he assumed that a large enough black hole would curve space in the region of the horizon, but only mildly so. But we know from our (limited and incomplete) forays into quantum gravity that we may have to account for a more dramatic curvature. To fully answer the question of “what’s gravity up to around an event horizon?” we may also have to fold in the same kind of quantum fuzziness that underlies theories of subatomic particles.

When we do that, however, we typically get uncontrollable infinities popping up everywhere in the math because such theories need to account for every possible exotic shape that spacetime can take. This is generally why we don’t have a theory of quantum gravity. That said, some brave theorists have dared to venture into those uncharted waters and have discovered some clever tricks (really hardcore stuff, too, like imaginary wormholes threading together in a complex mathematical space) to untangle some of the equations, showing that it may be possible to create scenarios where information can leak into the Hawking process.

Still other theorists have rejected this string-theory-driven approach to black holes and focus instead on the nature of space-time at the singularity. Their approaches consider whether space and time might come in discrete little chunks, the same way that energy levels and angular momentum do. In this view, the singularity is not an infinitely dense point but merely a really tiny one. And when the black hole evaporates, it doesn’t disappear completely—instead, it leaves behind a nugget of information-rich material. But those approaches run into major hurdles of their own, like having to figure out how to make the transition from a black hole with an inescapable horizon to a lump of matter existing bare naked in the Universe.

Ultimately, physicists remain intrigued by the information paradox because it potentially exposes a feature of quantum gravity and makes it available to our examination. Quantum gravity is usually the domain of the ultra-exotic: the initial moments of the Big Bang or unachievable particle collider energies. But black holes are real things in the real Universe; with enough determination, we could reach out and dip a toe into an event horizon.

If we can solve the information paradox, we just might be able to unlock quantum gravity, the unification of the forces, and more.

See the full article here .

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Ars Technica was founded in 1998 when Founder & Editor-in-Chief Ken Fisher announced his plans for starting a publication devoted to technology that would cater to what he called “alpha geeks”: technologists and IT professionals. Ken’s vision was to build a publication with a simple editorial mission: be “technically savvy, up-to-date, and more fun” than what was currently popular in the space. In the ensuing years, with formidable contributions by a unique editorial staff, Ars Technica became a trusted source for technology news, tech policy analysis, breakdowns of the latest scientific advancements, gadget reviews, software, hardware, and nearly everything else found in between layers of silicon.

Ars Technica innovates by listening to its core readership. Readers have come to demand devotedness to accuracy and integrity, flanked by a willingness to leave each day’s meaningless, click-bait fodder by the wayside. The result is something unique: the unparalleled marriage of breadth and depth in technology journalism. By 2001, Ars Technica was regularly producing news reports, op-eds, and the like, but the company stood out from the competition by regularly providing long thought-pieces and in-depth explainers.

And thanks to its readership, Ars Technica also accomplished a number of industry leading moves. In 2001, Ars launched a digital subscription service when such things were non-existent for digital media. Ars was also the first IT publication to begin covering the resurgence of Apple, and the first to draw analytical and cultural ties between the world of high technology and gaming. Ars was also first to begin selling its long form content in digitally distributable forms, such as PDFs and eventually eBooks (again, starting in 2001).

From “The New York Times” : “Nobel Prize in Physics Is Awarded to 3 Scientists for Work in Quantum Technology”

From “The New York Times”

10.4.22
Isabella Kwai
Cora Engelbrecht
Dennis Overbye

Awarding the prize on Tuesday, the committee said that the scientists’ work had “opened doors to another world.” Credit: Jonas Ekstromer/TT News Agency, via Associated Press

The Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser and Anton Zeilinger on Tuesday for work that has “laid the foundation for a new era of quantum technology,” the Nobel Committee for Physics said.

Alain Aspect.

John F. Clauser

Anton Zeilinger

The scientists have each conducted “groundbreaking experiments using entangled quantum states, where two particles behave like a single unit even when they are separated,” the committee said in a briefing. Their results, it said, cleared the way for “new technology based upon quantum information.”

The laureates’ research builds on the work of John Stewart Bell, a physicist who strove in the 1960s to understand whether particles, having flown too far apart for there to be normal communication between them, can still function in concert, also known as quantum entanglement.

According to quantum mechanics, particles can exist simultaneously in two or more places. They do not take on formal properties until they are measured or observed in some way. By taking measurements of one particle, like its position or “spin,” a change is observed in its partner, no matter how far away it has traveled from its pair.

Working independently, the three laureates did experiments that helped clarify a fundamental claim about quantum entanglement, which concerns the behavior of tiny particles, like electrons, that interacted in the past and then moved apart.

Dr. Clauser, an American, was the first in 1972. Using duct tape and spare parts at The DOE’s Lawrence Berkeley National Laboratory in Berkeley, Calif., he endeavored to measure quantum entanglement by firing thousands of photons in opposite directions to investigate a property known as polarization. When he measured the polarizations of photon pairs, they showed a correlation, proving that a principle called Bell’s inequality had been violated and that the photon pairs were entangled, or acting in concert.

The research was taken up 10 years later by Dr. Aspect, a French scientist, and his team at the University of Paris. And in 1998, Dr. Zeilinger, an Austrian physicist, led another experiment that considered entanglement among three or more particles.

Eva Olsson, a member of the Nobel Committee for Physics, noted that quantum information science had broad implications in areas like secure information transfer and quantum computing.

Quantum information science is a “vibrant and rapidly developing field,” she said. “Its predictions have opened doors to another world, and it has also shaken the very foundation of how we interpret measurements.”

The Nobel committee said the three scientists were being honored for their experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science.

“Being able to manipulate and manage quantum states and all their layers of properties gives us access to tools with unexpected potential,” the committee said in a statement on Twitter.

Dr. Zeilinger described the award as “an encouragement to young people.”

“The prize would not be possible without more than 100 young people who worked with me over the years and made all this possible,” he said.

Though he acknowledged that the award was recognizing the future applications of his work, he said, “My advice would be: Do what you find interesting, and don’t care too much about possible applications.”

It was the second of several such prizes to be awarded over the coming week. The Nobels, among the highest honors in science, recognize groundbreaking contributions in a variety of fields.

“I’m still kind of shocked, but it’s a very positive shock,” Dr. Zeilinger said of receiving the phone call informing him of the news.

See the full article here .

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From The Department of Energy: “How Stiff Is the Proton?”

From The Department of Energy

9.30.22
Contact
Mohammad Ahmed
North Carolina Central University and Triangle Universities Nuclear Laboratory
mahmed2@nccu.edu

Compton scattering setup at the High Intensity Gamma Ray Source. The central cylinder is the liquid hydrogen target. High energy gamma rays are scattered from the liquid hydrogen into eight large detectors that measure the gamma rays’ energy. Credit: Mohammad Ahmed, North Carolina Central University and Triangle Universities Nuclear Laboratory

The Science

The proton is a composite particle made up of fundamental building blocks of quarks and gluons. These components and their interactions determine the proton’s structure, including its electrical charges and currents. This structure deforms when exposed to external electric and magnetic (EM) fields, a phenomenon known as polarizability. The EM polarizabilities are a measure of the stiffness against the deformation induced by EM fields. By measuring the EM polarizabilities, scientists learn about the internal structure of the proton. This knowledge helps to validate scientific understanding of how nucleons (protons and neutrons) form by comparing the results to theoretical descriptions of gamma-ray scattering from nucleons. Scientists call this scattering process nucleon Compton scattering.

The Impact

When scientists examine the proton at a distance and scale where EM responses dominate, they can determine values of EM polarizabilities with high precision. To do so, they use the theoretical frame of Effective Field Theories (EFTs). The EFTs hold the promise of matching the description of the nucleon structure at low energies to the current theory of the strong nuclear force called quantum chromodynamics (QCD). In this research scientists validated EFTs using proton Compton scattering. This approach also validated the framework and methodology that underlie EFTs.

Summary

Proton Compton scattering is the process by which scientists scatter circularly or linearly polarized gamma rays from a hydrogen target (in this case, a liquid target), then measure the angular distribution of the scattered gamma rays. High-energy gamma rays carry strong enough EM fields that the response of the charges and currents in the nucleon becomes significant. In this study, scientists performed new measurements of Compton scattering from the proton at the High Intensity Gamma Ray Source (HIGS) at the Triangle Universities Nuclear Laboratory. This work provided a novel experimental approach for Compton scattering from the proton at low energies using polarized gamma rays. The study advances the need for new high-precision measurements at HIGS to improve the accuracy of proton and neutron polarizabilities determinations. These measurements validate the theories which link the low-energy description of nucleons to QCD.

Science paper:
Physical Review Letters

See the full article here.

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The The United States Department of Energy is a cabinet-level department of the United States Government concerned with the United States’ policies regarding energy and safety in handling nuclear material. Its responsibilities include the nation’s nuclear weapons program; nuclear reactor production for the United States Navy; energy conservation; energy-related research; radioactive waste disposal; and domestic energy production. It also directs research in genomics. the Human Genome Project originated in a DOE initiative. DOE sponsors more research in the physical sciences than any other U.S. federal agency, the majority of which is conducted through its system of National Laboratories. The agency is led by the United States Secretary of Energy, and its headquarters are located in Southwest Washington, D.C., on Independence Avenue in the James V. Forrestal Building, named for James Forrestal, as well as in Germantown, Maryland.

Formation and consolidation

In 1942, during World War II, the United States started the Manhattan Project, a project to develop the atomic bomb, under the eye of the U.S. Army Corps of Engineers. After the war in 1946, the Atomic Energy Commission (AEC) was created to control the future of the project. The Atomic Energy Act of 1946 also created the framework for the first National Laboratories. Among other nuclear projects, the AEC produced fabricated uranium fuel cores at locations such as Fernald Feed Materials Production Center in Cincinnati, Ohio. In 1974, the AEC gave way to the Nuclear Regulatory Commission, which was tasked with regulating the nuclear power industry and the Energy Research and Development Administration, which was tasked to manage the nuclear weapon; naval reactor; and energy development programs.

The 1973 oil crisis called attention to the need to consolidate energy policy. On August 4, 1977, President Jimmy Carter signed into law The Department of Energy Organization Act of 1977 (Pub.L. 95–91, 91 Stat. 565, enacted August 4, 1977), which created the Department of Energy. The new agency, which began operations on October 1, 1977, consolidated the Federal Energy Administration; the Energy Research and Development Administration; the Federal Power Commission; and programs of various other agencies. Former Secretary of Defense James Schlesinger, who served under Presidents Nixon and Ford during the Vietnam War, was appointed as the first secretary.

President Carter created the Department of Energy with the goal of promoting energy conservation and developing alternative sources of energy. He wanted to not be dependent on foreign oil and reduce the use of fossil fuels. With international energy’s future uncertain for America, Carter acted quickly to have the department come into action the first year of his presidency. This was an extremely important issue of the time as the oil crisis was causing shortages and inflation. With the Three-Mile Island disaster, Carter was able to intervene with the help of the department. Carter made switches within the Nuclear Regulatory Commission in this case to fix the management and procedures. This was possible as nuclear energy and weapons are responsibility of the Department of Energy.

Recent

On March 28, 2017, a supervisor in the Office of International Climate and Clean Energy asked staff to avoid the phrases “climate change,” “emissions reduction,” or “Paris Agreement” in written memos, briefings or other written communication. A DOE spokesperson denied that phrases had been banned.

In a May 2019 press release concerning natural gas exports from a Texas facility, the DOE used the term ‘freedom gas’ to refer to natural gas. The phrase originated from a speech made by Secretary Rick Perry in Brussels earlier that month. Washington Governor Jay Inslee decried the term “a joke”.

Facilities

The Department of Energy operates a system of national laboratories and technical facilities for research and development, as follows:

Ames Laboratory
Argonne National Laboratory
Brookhaven National Laboratory
Fermi National Accelerator Laboratory
Idaho National Laboratory
Lawrence Berkeley National Laboratory
Lawrence Livermore National Laboratory
Los Alamos National Laboratory
National Energy Technology Laboratory
National Renewable Energy Laboratory
Oak Ridge National Laboratory
Pacific Northwest National Laboratory
Princeton Plasma Physics Laboratory
Sandia National Laboratories
Savannah River National Laboratory
SLAC National Accelerator Laboratory
Thomas Jefferson National Accelerator Facility

Other major DOE facilities include
Albany Research Center
Bannister Federal Complex
Bettis Atomic Power Laboratory – focuses on the design and development of nuclear power for the U.S. Navy
Kansas City Plant
Knolls Atomic Power Laboratory – operates for Naval Reactors Program Research under the DOE (not a National Laboratory)
National Petroleum Technology Office
Nevada Test Site
New Brunswick Laboratory
Office of River Protection
Pantex
Radiological and Environmental Laboratory
Y-12 National Security Complex
Yucca Mountain nuclear waste repository
Other:

Pahute Mesa Airstrip – Nye County, Nevada, in supporting Nevada National Security Site

From The Technical University of Munich [Technische Universität München] (DE) And The Technical University of Dresden [Technische Universität Dresden] (DE) : “Quantum matter:: entanglement of many atoms detected for the first time”

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

And

The Technical University of Dresden [Technische Universität Dresden] (DE)

9.30.22

New insights into quantum phenomena at phase transitions

In the past, quantum phenomena could be investigated only in the realm of just a few atoms. A research team from the Technical University of Munich (TUM) and the Technical University of Dresden (TUD) has now discovered conditions for which quantum entanglement dominates on much larger scales. The results suggest new approaches to the exploration of quantum phenomena and their practical applications such as quantum computing.

Andreas Wendl preparing a superconducting magnet system. Credit: A. Heddergott /TUM.

To observe phase transitions in familiar temperature ranges, we can look at water. At 100°C it evaporates into a gas and at 0°C it freezes into ice. In all three states, the atoms display different forms of order that change abruptly across well-defined transitions. Such ordered states are also referred to as phases, separated accordingly by phase transitions. Material properties such as magnetism, superconductivity or ferroelectricity are also ordered phases, however, of the electrons in solids.

Near absolute zero, at -273.15°C, the behavior of materials can no longer be explained by classical theories. Here quantum mechanics plays a crucial role, in particular the phenomenon of entanglement, in which particles share a quantum mechanical state. If a phase transition occurs at absolute zero, for example by means of a magnetic force, the entanglement changes and specialists speak of a quantum phase transition. As for high temperatures, quantum phase transitions result in an abrupt change of the material properties.

New type of phase transition discovered

“Despite more than 30 years of extensive research dedicated to phase transitions in quantum materials, we previously assumed that the phenomenon of entanglement plays an important role at tiny distance and time scales only,” explains Matthias Vojta, Chair of Theoretical Solid State Physics at TUD. In their investigation of lithium holmium fluoride (LiHoF4), the team was able to demonstrate under which conditions quantum entanglement can be studied on much larger scales. “We discovered a new type of quantum transition in which magnetic domains play a decisive role.”

Spherical samples permit precise measurements

LiHoF4 is a ferromagnet at very low temperatures. However, if a strong magnetic field is applied exactly perpendicular to the preferred magnetic direction, the ferromagnetism vanishes entirely above a quantum phase transition. This phenomenon has been known for a long time. In their studies, the researchers now changed the direction of the magnetic field. Andreas Wendl, who conducted the experiments as part of his doctoral thesis work, explains: “We used spherical samples for our precision measurements. This allowed us to investigate the behavior in response to a small tilt of the magnetic field.”

In doing so, the researchers made a surprising observation. “We discovered that the quantum phase transition continues to exist, whereas it was previously believed that even the smallest tilt of the magnetic field would immediately suppress the transition,” says Christian Pfleiderer, professor of Experimental Physics for the Topology of Correlated Systems at TUM. Instead of the expected gradual variation in the material’s properties, the team observed an abrupt change – the defining feature of a phase transition.

The cause of these transitions according to the researchers is what is known as textures. These refer to the rough patterns in which the particles organize themselves in their microscopically ordered states. In ice these are mutually tilted crystallites and in magnets these are magnetic domains, also known as Weiss domains. Until now it was unclear whether textures can exhibit quantum phase transitions by themselves. The researchers have now discovered that this is possible and thus demonstrated that quantum entanglement also takes place at the level of textures – in other words for large numbers of atoms.

Significance for quantum technologies

On the basis of their data, the researchers have developed a new theoretical model. “For our analysis, we had to generalize existing microscopic models to take into account the tilt of the magnetic field,” says Heike Eisenlohr, who performed the calculations as part of her PhD thesis. “As an entirely new aspect, we then also calculated the feedback of the ferromagnetic domains on the microscopic properties.”

The discovery of the new quantum phase transitions and the underlying theoretical model promise to be important as a foundation and general frame of reference for research on quantum phenomena in materials, as well as for new applications: “Quantum entanglement could be controlled and applied in such technologies as quantum sensors and quantum computers,” says Vojta. Pfleiderer adds: “Our work relates to fundamental research. However, it could soon have a direct impact on real-world applications with targeted use of the newly discovered material properties.”

Science paper:
Nature

See the full article here .

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

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

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

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

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

Measured by the number of DAX board members, no top manager in the German economy was a graduate of the TU Dresden in 2019.

According to the QS Engineering and Technology Ranking the university ranked 113th worldwide and 5th in Germany. According to the Times Higher Education World University Rankings the university ranked 157th worldwide and in engineering & technology the university ranked 90th worldwide. Moreover, According to Reuters, the university was ranked 79th in the list of ‘Most Innovative Universities Ranking 2019’.

The Eduniversal Business Schools ranking ranks the university’s Faculty of Business and Economics with 3 out of 5 palmes of excellence. According to the university ranking 2016 of the German business magazine Wirtschaftswoche the university ranked 7th in Germany in computer science and mechanical engineering and 6th in Germany in business informatics and engineering management. The university did not take first place in any of the ranked subjects: Business Administration, Business informatics, Engineering management, Natural Sciences, Computer Science, Electrical Engineering, Mechanical Engineering and Economics.

International cooperations

As one of the first universities in Germany it has opened a branch in Hanoi, Vietnam offering a Master’s course in mechatronics. It also maintains close partnerships with leading universities around the world, e.g. Boston University, Georgetown University, Harvard Medical School, Tongji University [同济大学](CN) and Pohang University of Science and Technology [포항공과대학교](KR).

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

A University of Excellence under the German Universities Excellence Initiative, TUM is consistently ranked among the leading universities in the European Union and its researchers and alumni include 17 Nobel laureates and 23 Leibniz Prize winners.

Research

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

In the QS World Rankings, TUM is ranked 25th (worldwide) in engineering and technology, 28th in the natural sciences, 35th in computer science, and 50th place overall. It is the highest ranked German university in those subject areas.

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

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

In the 2020 Global University Employability Ranking of the Times Higher Education World Rankings, TUM was ranked 12th in the world and 3rd in Europe. TUM is ranked 7th overall in Reuters’ 2019 European Most Innovative University ranking.

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

Partnerships

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

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

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

From The Pritzker School of Molecular Engineering: “Engineering robust and scalable molecular qubits”

From The Pritzker School of Molecular Engineering

At

The University of Chicago

9.27.22
Meredith Fore

By placing molecular qubits in an asymmetric crystal array, Prof. David Awschalom and his team found that certain quantum states were much less sensitive to external magnetic fields. (Image courtesy of Awschalom Group, D. Laorenza/MIT)

The concept of “symmetry” is essential to fundamental physics: a crucial element in everything from subatomic particles to macroscopic crystals. Accordingly, a lack of symmetry—or asymmetry—can drastically affect the properties of a given system.

Qubits, the quantum analog of computer bits for quantum computers, are extremely sensitive—the barest disturbance in a qubit system is enough for it to lose any quantum information it might have carried. Given this fragility, it seems intuitive that qubits would be most stable in a symmetric environment. However, for a certain type of qubit—a molecular qubit—the opposite is true.

Researchers from the University of Chicago’s Pritzker School of Molecular Engineering (PME), the University of Glasgow, and the Massachusetts Institute of Technology have found that molecular qubits are much more stable in an asymmetric environment, expanding the possible applications of such qubits, especially as biological quantum sensors.

The work was published in August in Physical Review X [below].

“Molecular qubits are remarkably versatile, since they can be custom-engineered and placed in a variety of different environments,” said David Awschalom, the Liew Family Professor in Molecular Engineering and Physics at UChicago, senior scientist at The DOE’s Argonne National Laboratory, director of the Chicago Quantum Exchange, and director of Q-NEXT, a Department of Energy Quantum Information Science Center. “Developing this method of stabilizing them opens new doors for potential applications of this emerging technology.”

Using a system as a qubit requires it to have two quantum states that can correspond to “0” and “1”, as in a classical computer. But quantum states are fragile, and will collapse if disturbed in any way. Quantum scientists have been pushing the limits of how long they can make a qubit hold a quantum state before collapsing, also known as “coherence time.”

Shielding qubits from as much external influence as possible is one way to try to increase their coherence time. And by placing the molecular qubits in an asymmetric crystal array, Awschalom and his team found that certain quantum states were much less sensitive to external magnetic fields, and thus had longer coherence times: 10 µs, compared to 2 µs for identical qubits in a symmetric crystal array.

Dan Laorenza, a chemistry graduate student at MIT who worked on the project, says the asymmetric environment provides “coherence protection” that could allow the qubits to keep their quantum information even if placed in more chaotic places.

“We now understand a direct and reliable mechanism to improve coherence of molecular qubits in magnetically noisy environments,” he said. “Most importantly, this asymmetric environment is easily translated to many other molecular systems, especially for molecules put in amorphous environments like those found in biology.”

Qubit quantum sensors have myriad potential applications in biological systems, especially in medical contexts; but these systems are known for being unstructured and noisy, which makes maintaining the coherence of these qubit sensors a very difficult challenge. Learning why an asymmetric environment stabilizes molecular qubits against magnetic fields could lead to better sensors in these research fields.

Science paper:
Physical Review X

See the full article here .

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Stem Education Coalition

The Pritzker School of Molecular Engineering is the first school of engineering at the University of Chicago. It was founded as the Institute for Molecular Engineering in 2011 by the university in partnership with Argonne National Laboratory. When the program was raised to the status of a school in 2019, it became the first school dedicated to molecular engineering in the United States. It is named for a major benefactor, the Pritzker Foundation.

The scientists, engineers, and students at PME use scientific research to pursue engineering solutions. The school does not have departments. Instead, it organizes its research around interdisciplinary “themes”: immuno-engineering, quantum engineering, autonomous materials, and water and energy. PME works toward technological advancements in areas of global importance, including sustainable energy and natural resources, immunotherapy-based approaches to cancer, “unhackable” communications networks, and a clean global water supply. The school plans to expand its research areas to address more issues of global importance.

IME was established in 2011, after three years of discussion and review. It was the largest academic program founded by the University of Chicago since 1988, when the Harris School of Public Policy Studies was established.

Matthew Tirrell was appointed founding Pritzker Director of IME in July 2011. The Pritzker Directorship honors the Pritzker Foundation, which donated a large gift in support of the institute. Tirrell is a researcher in biomolecular engineering and nanotechnology. His honors include election to The National Academy of Engineering, The American Academy of Arts and Sciences, and The National Academy of Sciences. He became dean of PME in 2019.

The William Eckhardt Research Center (WERC), which houses the school and part of the Physical Sciences Division, was constructed between 2011 and 2015. The WERC was named for alumnus William Eckhardt, in recognition of his donation to support scientific research at the university.

In 2019, the school received more than $23.1 million in research funding. From 2011 to 2019, faculty at the school have filed 69 invention disclosures and have created six companies.

On May 28, 2019, the University of Chicago announced a $100 million commitment from the Pritzker Foundation to support the institute’s transition to a school—the first school of molecular engineering in the U.S. The Pritzker Foundation helped establish the school with a new donation of $75 million, adding to an earlier $25 million donation that supported the institute and the construction of the Pritzker Nanofabrication Facility. In 2019, PME became the university’s first new school in three decades.

PME offers a graduate program in molecular engineering for both Master and Ph.D. students, as well as an undergraduate major and minor in molecular engineering offered with the College of the University of Chicago.

The institute began accepting applications to its doctoral program in fall 2013. The first class of graduate students was matriculated the following fall. In 2019, the school had 28 faculty members, 91 undergraduate students, 134 graduate students, and 75 postdoctoral fellows.

The graduate program curriculum includes various science and engineering disciplines, product design, entrepreneurship, and communication. The program is interdisciplinary, featuring a connected art program called STAGE Lab. STAGE Lab creates plays and films in the context of scientific research at PME.

The undergraduate major was added in spring 2015. It was the first engineering major offered at the University of Chicago. In 2018, the first undergraduate class received degrees in molecular engineering. When the school was established in 2019, it announced plans to expand its undergraduate offerings.

David Awschalom, a professor at PME, said the school has contributed to Chicago becoming a hub for quantum education and research. PME offers an advanced degree in quantum science and engineering. It also partnered with Harvard University to launch the Quantum Information Science and Engineering Network, a graduate student training program in quantum science and engineering. Participating students are paired with two mentors—one from academia and one from industry. The program was funded by a $1.6 million award from the National Science Foundation.

The school’s partnership with The DOE’s Argonne National Laboratory provides additional opportunities for research and innovation. Argonne’s facilities include the Advanced Photon Source, the Argonne Leadership Computing Facility, and the Center for Nanoscale Materials. The lab also has experience licensing new technology for industrial and commercial applications.

PME’s educational outreach initiatives include K-12 programs with events and internships throughout the year. In 2019, with the establishment of PME, the school also launched a partnership with City Colleges of Chicago. The multi-year program connects City College students interested in STEM fields with PME faculty and labs, with the goal of enabling these students to transfer into four-year STEM degree programs.

The University of Chicago is an urban research university that has driven new ways of thinking since 1890. Our commitment to free and open inquiry draws inspired scholars to our global campuses, where ideas are born that challenge and change the world.

We empower individuals to challenge conventional thinking in pursuit of original ideas. Students in the College develop critical, analytic, and writing skills in our rigorous, interdisciplinary core curriculum. Through graduate programs, students test their ideas with University of Chicago scholars, and become the next generation of leaders in academia, industry, nonprofits, and government.

University of Chicago research has led to such breakthroughs as discovering the link between cancer and genetics, establishing revolutionary theories of economics, and developing tools to produce reliably excellent urban schooling. We generate new insights for the benefit of present and future generations with our national and affiliated laboratories: DOE’s Argonne National Laboratory, DOE’s Fermi National Accelerator Laboratory , and the Marine Biological Laboratory in Woods Hole, Massachusetts.
The University of Chicago is enriched by the city we call home. In partnership with our neighbors, we invest in Chicago’s mid-South Side across such areas as health, education, economic growth, and the arts. Together with our medical center, we are the largest private employer on the South Side.

In all we do, we are driven to dig deeper, push further, and ask bigger questions—and to leverage our knowledge to enrich all human life. Our diverse and creative students and alumni drive innovation, lead international conversations, and make masterpieces. Alumni and faculty, lecturers and postdocs go on to become Nobel laureates, CEOs, university presidents, attorneys general, literary giants, and astronauts. The University of Chicago is a private research university in Chicago, Illinois. Founded in 1890, its main campus is located in Chicago’s Hyde Park neighborhood. It enrolled 16,445 students in Fall 2019, including 6,286 undergraduates and 10,159 graduate students. The University of Chicago is ranked among the top universities in the world by major education publications, and it is among the most selective in the United States.

The university is composed of one undergraduate college and five graduate research divisions, which contain all of the university’s graduate programs and interdisciplinary committees. Chicago has eight professional schools: the Law School, the Booth School of Business, the Pritzker School of Medicine, the School of Social Service Administration, the Harris School of Public Policy, the Divinity School, the Graham School of Continuing Liberal and Professional Studies, and the Pritzker School of Molecular Engineering. The university has additional campuses and centers in London, Paris, Beijing, Delhi, and Hong Kong, as well as in downtown Chicago.

University of Chicago scholars have played a major role in the development of many academic disciplines, including economics, law, literary criticism, mathematics, religion, sociology, and the behavioralism school of political science, establishing the Chicago schools in various fields. Chicago’s Metallurgical Laboratory produced the world’s first man-made, self-sustaining nuclear reaction in Chicago Pile-1 beneath the viewing stands of the university’s Stagg Field. Advances in chemistry led to the “radiocarbon revolution” in the carbon-14 dating of ancient life and objects. The university research efforts include administration of DOE’s Fermi National Accelerator Laboratory and DOE’s Argonne National Laboratory, as well as the U Chicago Marine Biological Laboratory in Woods Hole, Massachusetts (MBL). The university is also home to the University of Chicago Press, the largest university press in the United States. The Barack Obama Presidential Center is expected to be housed at the university and will include both the Obama presidential library and offices of the Obama Foundation.

The University of Chicago’s students, faculty, and staff have included 100 Nobel laureates as of 2020, giving it the fourth-most affiliated Nobel laureates of any university in the world. The university’s faculty members and alumni also include 10 Fields Medalists, 4 Turing Award winners, 52 MacArthur Fellows, 26 Marshall Scholars, 27 Pulitzer Prize winners, 20 National Humanities Medalists, 29 living billionaire graduates, and have won eight Olympic medals.

The University of Chicago is enriched by the city we call home. In partnership with our neighbors, we invest in Chicago’s mid-South Side across such areas as health, education, economic growth, and the arts. Together with our medical center, we are the largest private employer on the South Side.

Research

According to the National Science Foundation, University of Chicago spent $423.9 million on research and development in 2018, ranking it 60th in the nation. It is classified among “R1: Doctoral Universities – Very high research activity” and is a founding member of the Association of American Universities and was a member of the Committee on Institutional Cooperation from 1946 through June 29, 2016, when the group’s name was changed to the Big Ten Academic Alliance. The University of Chicago is not a member of the rebranded consortium, but will continue to be a collaborator.

The university operates more than 140 research centers and institutes on campus. Among these are the Oriental Institute—a museum and research center for Near Eastern studies owned and operated by the university—and a number of National Resource Centers, including the Center for Middle Eastern Studies. Chicago also operates or is affiliated with several research institutions apart from the university proper. The university manages DOE’s Argonne National Laboratory, part of the United States Department of Energy’s national laboratory system, and co-manages DOE’s Fermi National Accelerator Laboratory, a nearby particle physics laboratory, as well as a stake in the Apache Point Observatory in Sunspot, New Mexico.
_____________________________________________________________________________________

SDSS Telescope at Apache Point Observatory, near Sunspot NM, USA, Altitude 2,788 meters (9,147 ft).

Apache Point Observatory, near Sunspot, New Mexico Altitude 2,788 meters (9,147 ft).
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Faculty and students at the adjacent Toyota Technological Institute at Chicago collaborate with the university. In 2013, the university formed an affiliation with the formerly independent Marine Biological Laboratory in Woods Hole, Mass. Although formally unrelated, the National Opinion Research Center is located on Chicago’s campus.

From The Simons Foundation : “Artificial Intelligence Reduces a 100000-Equation Quantum Physics Problem to Only Four Equations”

From The Simons Foundation

9.26.22
Thomas Sumner

Researchers at the Flatiron Institute and their colleagues trained a machine learning tool to capture the physics of electrons moving on a lattice using far fewer equations than would typically be required, all without sacrificing accuracy.

A visualization of a mathematical apparatus used to capture the physics and behavior of electrons moving on a lattice. Each pixel represents a single interaction between two electrons. Until now, accurately capturing the system required around 100,000 equations — one for each pixel. Using machine learning, scientists reduced the problem to just four equations. That means a similar visualization for the compressed version would need just four pixels. Domenico Di Sante/Flatiron Institute.

Using artificial intelligence, physicists have compressed a daunting quantum problem that until now required 100,000 equations into a bite-size task of as few as four equations — all without sacrificing accuracy. The work, published in the September 23 issue of Physical Review Letters [below], could revolutionize how scientists investigate systems containing many interacting electrons. Moreover, if scalable to other problems, the approach could potentially aid in the design of materials with sought-after properties such as superconductivity or utility for clean energy generation.

“We start with this huge object of all these coupled-together differential equations; then we’re using machine learning to turn it into something so small you can count it on your fingers,” says study lead author Domenico Di Sante, a visiting research fellow at the Flatiron Institute’s Center for Computational Quantum Physics (CCQ) in New York City and an assistant professor at the University of Bologna in Italy.

The formidable problem concerns how electrons behave as they move on a gridlike lattice. When two electrons occupy the same lattice site, they interact. This setup, known as the Hubbard model, is an idealization of several important classes of materials and enables scientists to learn how electron behavior gives rise to sought-after phases of matter, such as superconductivity, in which electrons flow through a material without resistance. The model also serves as a testing ground for new methods before they’re unleashed on more complex quantum systems.

The Hubbard model is deceptively simple, however. For even a modest number of electrons and cutting-edge computational approaches the problem requires serious computing power. That’s because when electrons interact, their fates can become quantum mechanically entangled: Even once they’re far apart on different lattice sites, the two electrons can’t be treated individually, so physicists must deal with all the electrons at once rather than one at a time. With more electrons, more entanglements crop up, making the computational challenge exponentially harder.

One way of studying a quantum system is by using what’s called a renormalization group. That’s a mathematical apparatus physicists use to look at how the behavior of a system — such as the Hubbard model — changes when scientists modify properties such as temperature or look at the properties on different scales. Unfortunately, a renormalization group that keeps track of all possible couplings between electrons and doesn’t sacrifice anything can contain tens of thousands, hundreds of thousands or even millions of individual equations that need to be solved. On top of that, the equations are tricky: Each represents a pair of electrons interacting.

Di Sante and his colleagues wondered if they could use a machine learning tool known as a neural network to make the renormalization group more manageable. The neural network is like a cross between a frantic switchboard operator and survival-of-the-fittest evolution. First, the machine learning program creates connections within the full-size renormalization group. The neural network then tweaks the strengths of those connections until it finds a small set of equations that generates the same solution as the original, jumbo-size renormalization group. The program’s output captured the Hubbard model’s physics even with just four equations.

“It’s essentially a machine that has the power to discover hidden patterns,” Di Sante says. “When we saw the result, we said, ‘Wow, this is more than what we expected.’ We were really able to capture the relevant physics.”

Training the machine learning program required a lot of computational muscle, and the program ran for entire weeks. The good news, Di Sante says, is that now that they have their program coached, they can adapt it to work on other problems without having to start from scratch. He and his collaborators are also investigating just what the machine learning is actually “learning” about the system, which could provide additional insights that might otherwise be hard for physicists to decipher.

Ultimately, the biggest open question is how well the new approach works on more complex quantum systems such as materials in which electrons interact at long distances. In addition, there are exciting possibilities for using the technique in other fields that deal with renormalization groups, Di Sante says, such as cosmology and neuroscience.

Di Sante co-authored the new study with CCQ guest researcher Matija Medvidović (a graduate student at Columbia University), Alessandro Toschi of TU Wien in Vienna, Giorgio Sangiovanni of the University of Würzburg in Germany, Cesare Franchini of the University of Bologna in Italy, CCQ and Center for Computational Mathematics senior research scientist Anirvan M. Sengupta, and CCQ co-director Andy Millis. Di Sante’s time at the CCQ was supported by a Marie Curie International Fellowship, which encourages transnational scientific collaboration.

Science paper:
Physical Review Letters

See the full article here.

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Mission and Model

The Simons Foundation’s mission is to advance the frontiers of research in mathematics and the basic sciences.

Co-founded in New York City by Jim and Marilyn Simons, the foundation exists to support basic — or discovery-driven — scientific research undertaken in the pursuit of understanding the phenomena of our world.

The Simons Foundation’s support of science takes two forms: We support research by making grants to individual investigators and their projects through academic institutions, and, with the launch of the Flatiron Institute in 2016, we now conduct scientific research in-house, supporting teams of top computational scientists.

From The University of California-Santa Barbara And The University of Maryland And The University of Washington : “A Different Kind of Chaos”

From The University of California-Santa Barbara

And

The University of Maryland

And

The University of Washington

9.26.22
Sonia Fernandez

Physicists answer a decades-old question about interacting quantum particles in a disordered system.

The experimental setup used by the Weld Lab. Photo Credit: Tony Mastres.

Physicists at UC Santa Barbara and The University of Maryland, and also at the University of Washington have found an answer to the longstanding physics question: How do interparticle interactions affect dynamical localization?

“It’s a really old question inherited from condensed matter physics,” said David Weld, an experimental physicist at UCSB with specialties in ultracold atomic physics and quantum simulation. The question falls into the category of ‘many-body’ physics, which interrogates the physical properties of a quantum system with multiple interacting parts. While many-body problems have been a matter of research and debate for decades, the complexity of these systems, with quantum behaviors such as superposition and entanglement, lead to multitudes of possibilities, making it impossible to solve through calculation alone. “Many aspects of the problem are beyond the reach of modern computers,” Weld added.

Fortunately, this problem was not beyond the reach of an experiment that involves ultracold lithium atoms and lasers. So, what emerges when you introduce interaction in a disordered, chaotic quantum system?

A “weird quantum state,” according to Weld. “It’s a state which is anomalous, with properties which in some sense lie between the classical prediction and the non-interacting quantum prediction.”

The physicists’ results are published in the journal Nature Physics [below].

“Anomalous Non-localization”
When it comes to strange counterintuitive behavior the quantum world does not disappoint. Take for instance a regular pendulum, which would behave exactly how we would expect it to when subjected to pulses of energy.

“If you kick it and shake it up and down every once in a while, a classical pendulum will continuously absorb energy, start to wiggle all over the place and explore the whole parameter space chaotically,” Weld said.

In quantum systems chaos looks different. Instead of movement, disorder can bring particles to a kind of standstill. And while a kicked quantum pendulum or “rotor” might first absorb energy from the kicks — similar to a classical pendulum — with repeated kicks, the system stops absorbing energy and the momentum distribution freezes, in what’s known as a dynamically localized state. This localization is closely analogous to the behavior of a “dirty” electronic solid, in which disorder results in immobile, localized electrons, causing the solid to transition from being a metal, or a conductor (moving electrons), to being an insulator.

While this state of localization has been explored for decades in the context of single, noninteracting particles, what happens in a disordered system with multiple interacting electrons? Questions like this and related aspects of quantum chaos were on the minds of Weld and his co-author, University of Maryland theorist Victor Galitski, during a discussion several years ago when Galitski was visiting Santa Barbara.

“What Victor raised was the question of what happens if, instead of this pure non-interacting quantum system which is stabilized by interference, you have a bunch of these rotors and they can all bump into and interact with each other,” Weld recalled. “Does the localization persist, or is it destroyed by the interactions?”

“Indeed, it is a very difficult question that relates to foundations of statistical mechanics and the basic notion of ergodicity, whereby most interacting systems eventually thermalize into a universal state,” said Galitski.

Imagine for a moment pouring cold milk into hot coffee. The particles in your cup will, over time and through their interactions, arrange themselves into a uniform, equilibrium state that is neither purely hot coffee or cold milk. This type of behavior — thermalization — was expected of all interacting systems. That is, until about 16 years ago when it was argued that disorder in a quantum system was thought to result in many-body localization (MBL).

“This phenomenon, which was recognized by the Lars Onsager Prize earlier this year, is difficult to rigorously prove theoretically or establish experimentally,” Galitski said.

Weld’s group had the technology and expertise to shed light on the situation, literally. In their lab is a gas of 100,000 ultracold lithium atoms suspended in a standing wave of light. Each atom represents a quantum rotor that can be kicked by laser pulses.

“We can use a tool called a Feshbach resonance to keep the atoms cloaked from each other, or we can make them bounce off each other with arbitrarily strong interactions,” Weld said. With a turn of a knob, the researchers could make the lithium atoms go from line dance to mosh pit and capture their behaviors.

As expected, when the atoms were invisible to each other they took the laser kicking up to a certain point, after which they stopped moving in their dynamically localized state, despite repeated kicks. But when the researchers dialed up the interaction, not only did the localized state diminish, but the system appeared to absorb energy from the repeated kicks, mimicking classical chaotic behavior.

However, Weld pointed out, while the interacting disordered quantum system was absorbing energy, it was doing so at a much slower rate than would a classical system.

“What we’re seeing is something that absorbs energy, but not as well as a classical system can,” he said. “And it seems like the energy is growing roughly with the square root of time instead of linearly with time. So the interactions aren’t making it classical; it’s still a weird quantum state exhibiting anomalous non-localization.”

Testing for Chaos

Weld’s team used a technique called an “echo” in which the kinetic evolution is run forward and then backward to directly measure the way in which interactions destroy time reversibility. This destruction of time reversibility is a key signature of quantum chaos.

“Another way to think about this is to ask: How much memory of the initial state does the system have after some time?” said co-author Roshan Sajjad, a graduate student researcher on the lithium team. In the absence of any perturbations such as stray light or gas collisions, he explained, the system should be able to return to its initial state if the physics is run backward. “In our experiment, we reverse time by reversing the phase of the kicks, ‘undoing’ the effects of the first normal set of kicks,” he said. “Part of our fascination was that different theories had predicted different behaviors on the outcome of this type of interacting setup, but no one had ever done the experiment.”

“The rough idea of chaos is that even though the laws of motion are time-reversible, a many-particle system can be so complicated and sensitive to perturbations that is practically impossible to return to its initial state,” said lead author Alec Cao. The twist was that in an effectively disordered (localized) state, the interactions broke the localization somewhat even as the system lost its capacity to be time-reversed, he explained.

“Naively, you’d expect interactions to ruin time-reversal, but we saw something more interesting: A little bit of interaction actually helps!” Sajjad added. “This was one of the more surprising results of this work.”

Weld, Galitski and their teams weren’t the only ones to witness this fuzzy quantum state. University of Washington physicist Subhadeep Gupta and his team ran a complementary experiment at the same time, producing similar results using heavier atoms in a one-dimensional context. That result is published alongside those of UC Santa Barbara’s and University of Maryland’s in Nature Physics.

“The experiments at UW operated in a very difficult physical regime with 25-times-heavier atoms restricted to move in one dimension only, yet also measured weaker-than-linear energy growth from periodic kicking, shedding light on an area where theoretical results have been in conflict,” said Gupta, whose group collaborated with theorist Chuanwei Zhang and his team at the University of Texas in Dallas.

These findings, like many important physics results, open up more questions and pave the way for more quantum chaos experiments, where the coveted link between classical and quantum physics may be uncovered.

“David’s experiment is the first attempt to probe a dynamical version of MBL in a more controlled laboratory setting,” Galitski commented. “While it has not unambiguously resolved the fundamental question one way or another, the data show something strange is going on.”

“How can we understand these results in the context of the very large body of work on many-body localization in condensed matter systems?” Weld asked. “How can we characterize this state of matter? We observe that the system is delocalizing, but not with the expected linear time dependence; what’s going on there? We’re looking forward to future experiments exploring these and other questions.”

Science paper:
Nature Physics

See the full article here .

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Please help promote STEM in your local schools.

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The University of California-Santa Barbara is a public land-grant research university in Santa Barbara, California, and one of the ten campuses of the University of California system. Tracing its roots back to 1891 as an independent teachers’ college, The University of California-Santa Barbara joined the University of California system in 1944, and is the third-oldest undergraduate campus in the system.

The university is a comprehensive doctoral university and is organized into five colleges and schools offering 87 undergraduate degrees and 55 graduate degrees. It is classified among “R1: Doctoral Universities – Very high research activity”. According to the National Science Foundation, The University of California-Santa Barbara spent $235 million on research and development in fiscal year 2018, ranking it 100th in the nation. In his 2001 book The Public Ivies: America’s Flagship Public Universities, author Howard Greene labeled The University of California-Santa Barbara a “Public Ivy”.

The University of California-Santa Barbara is a research university with 10 national research centers, including the Kavli Institute for Theoretical Physics and the Center for Control, Dynamical-Systems and Computation. Current University of California-Santa Barbara faculty includes six Nobel Prize laureates; one Fields Medalist; 39 members of the National Academy of Sciences; 27 members of the National Academy of Engineering; and 34 members of the American Academy of Arts and Sciences. The University of California-Santa Barbara was the No. 3 host on the ARPANET and was elected to The Association of American Universities in 1995. The faculty also includes two Academy and Emmy Award winners and recipients of a Millennium Technology Prize; an IEEE Medal of Honor; a National Medal of Technology and Innovation; and a Breakthrough Prize in Fundamental Physics.
The University of California-Santa Barbara Gauchos compete in the Big West Conference of the NCAA Division I. The Gauchos have won NCAA national championships in men’s soccer and men’s water polo.

History

The University of California-Santa Barbara traces its origins back to the Anna Blake School, which was founded in 1891, and offered training in home economics and industrial arts. The Anna Blake School was taken over by the state in 1909 and became the Santa Barbara State Normal School which then became the Santa Barbara State College in 1921.

In 1944, intense lobbying by an interest group in the City of Santa Barbara led by Thomas Storke and Pearl Chase persuaded the State Legislature, Gov. Earl Warren, and the Regents of the University of California to move the State College over to the more research-oriented University of California system. The State College system sued to stop the takeover but the governor did not support the suit. A state constitutional amendment was passed in 1946 to stop subsequent conversions of State Colleges to University of California campuses.

From 1944 to 1958, the school was known as Santa Barbara College of the University of California, before taking on its current name. When the vacated Marine Corps training station in Goleta was purchased for the rapidly growing college Santa Barbara City College moved into the vacated State College buildings.

Originally the regents envisioned a small several thousand–student liberal arts college a so-called “Williams College of the West”, at Santa Barbara. Chronologically, The University of California-Santa Barbara is the third general-education campus of the University of California, after The University of California-Berzerkeley and The University of California-Los Angeles (the only other state campus to have been acquired by the University of California system). The original campus the regents acquired in Santa Barbara was located on only 100 acres (40 ha) of largely unusable land on a seaside mesa. The availability of a 400-acre (160 ha) portion of the land used as Marine Corps Air Station Santa Barbara until 1946 on another seaside mesa in Goleta, which the regents could acquire for free from the federal government, led to that site becoming the Santa Barbara campus in 1949.

Originally only 3000–3500 students were anticipated but the post-WWII baby boom led to the designation of general campus in 1958 along with a name change from “Santa Barbara College” to “University of California-Santa Barbara,” and the discontinuation of the industrial arts program for which the state college was famous. A chancellor- Samuel B. Gould- was appointed in 1959.

In 1959 The University of California-Santa Barbara professor Douwe Stuurman hosted the English writer Aldous Huxley as the university’s first visiting professor. Huxley delivered a lectures series called The Human Situation.

In the late ’60s and early ’70s The University of California-Santa Barbara became nationally known as a hotbed of anti–Vietnam War activity. A bombing at the school’s faculty club in 1969 killed the caretaker Dover Sharp. In the spring of 1970 multiple occasions of arson occurred including a burning of the Bank of America branch building in the student community of Isla Vista during which time one male student Kevin Moran was shot and killed by police. The University of California-Santa Barbara ‘s anti-Vietnam activity impelled then-Gov. Ronald Reagan to impose a curfew and order the National Guard to enforce it. Armed guardsmen were a common sight on campus and in Isla Vista during this time.

In 1995 The University of California-Santa Barbara was elected to The Association of American Universities– an organization of leading research universities with a membership consisting of 59 universities in the United States (both public and private) and two universities in Canada.

On May 23, 2014 a killing spree occurred in Isla Vista, California, a community in close proximity to the campus. All six people killed during the rampage were students at The University of California-Santa Barbara. The murderer was a former Santa Barbara City College student who lived in Isla Vista.

Research activity

According to the National Science Foundation, The University of California-Santa Barbara spent $236.5 million on research and development in fiscal 2013, ranking it 87th in the nation.

From 2005 to 2009 UCSB was ranked fourth in terms of relative citation impact in the U.S. (behind Massachusetts Institute of Technology, California Institute of Technology, and Princeton University) according to Thomson Reuters.

The University of California-Santa Barbara hosts 12 National Research Centers, including The Kavli Institute for Theoretical Physics, the National Center for Ecological Analysis and Synthesis, the Southern California Earthquake Center, the UCSB Center for Spatial Studies, an affiliate of the National Center for Geographic Information and Analysis, and the California Nanosystems Institute. Eight of these centers are supported by The National Science Foundation. UCSB is also home to Microsoft Station Q, a research group working on topological quantum computing where American mathematician and Fields Medalist Michael Freedman is the director.

Research impact rankings

The Times Higher Education World University Rankings ranked The University of California-Santa Barbara 48th worldwide for 2016–17, while the Academic Ranking of World Universities (ARWU) in 2016 ranked https://www.nsf.gov/ 42nd in the world; 28th in the nation; and in 2015 tied for 17th worldwide in engineering.

In the United States National Research Council rankings of graduate programs, 10 University of California-Santa Barbara departments were ranked in the top ten in the country: Materials; Chemical Engineering; Computer Science; Electrical and Computer Engineering; Mechanical Engineering; Physics; Marine Science Institute; Geography; History; and Theater and Dance. Among U.S. university Materials Science and Engineering programs, The University of California-Santa Barbara was ranked first in each measure of a study by the National Research Council of the NAS.

The Centre for Science and Technologies Studies at