Research, teaching and outreach in Physics at UW–Madison
Faculty
Pupa Gilbert elected Fellow of the Mineralogical Society of America
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Congrats to Prof. Pupa Gilbert on her election as a Fellow of the Mineralogical Society of America! Members who have contributed significantly to the advancement of mineralogy, crystallography, geochemistry, petrology, or allied sciences and whose scientific contribution utilized mineralogical studies or data, may be designated as Fellows upon proper accreditation by the Committee on Nomination for Fellows and election by the Council. The number of fellows elected each year cannot exceed 0.5% of MSA membership.
Fellows newly elected in 2020 are Jeffrey Catalano, Sylvie Demouchy, Pupa Gilbert, Jun-ichi Kimura, Othmar Muntener, Marc Norman, Alison Pawley, Mark Rivers, Ian Swainson, and Takashi Yoshino.
From bird feathers that allow for perfectly efficient flight to the bacterial enzyme that fixes nitrogen to help plants grow, nature has had a lot of time to figure things out. “There are so many things we need to be learning how to do from nature, because our methods are still much inferior to those!” says UW–Madison’s newest physics professor, Uwe Bergmann, the Martin L. Perl Professor in Ultrafast X-ray Science. “I think we are going in this direction of learning more and more from nature and using this knowledge to run our world sustainably, but still in a modern way. And that theme brings physicists and many other domains together.”
Bergmann is a physicist who develops and applies x-ray techniques to chemical, biological, engineering, and even archaeological research questions, trying to understand at the atomic level what nature has perfected over a few billion years. Prior to joining the Department on December 1, Bergmann was a Scientist at SLAC. Here, he will focus his research program on continuing to develop and apply novel x-ray techniques. To welcome Bergmann, we sat down for a (virtual) interview.
What is an overview of your research?
My research is developing and applying x-ray methods to solve problems. And these problems can be uncovering hidden writings in ancient books or the chemical elements buried in fossils to reveal the color in the original animal; studying photosynthetic water splitting to understanding the structure of liquid water; and making movies of a molecule carrying out specific work.
What techniques do you use in your research?
I use mainly x-ray techniques, and we do x-ray spectroscopy and sometimes also x-ray scattering and diffraction. The basic difference is that diffraction and scattering looks at the geometric structure — where are the atoms? — and spectroscopy looks at the chemical structure — where are the electrons? Recently we have been using powerful new x-ray lasers, where you can make ultrafast movies showing how chemical bonds are changing in real time. I also use x-ray fluorescence, which is a very powerful imaging technique for creating elemental maps showing the chemical composition of fossils for example.
Once your lab is up and running in Madison, what big projects will you focus on first?
I want to set up a new ultrafast x-UV laser system, able to making these molecular movies with femtosecond resolution. We want to make movies of fast chemical reactions and structural changes; when you expose a material to a light pulse and then watch how the atoms and electrons rearrange after the pulse. This is important for the next generation of advanced materials and a famous example is the water splitting reaction in plants to make O2. We still do not exactly know the mechanism of how these two water molecules are brought in, split up, and forced to make the bond to form O2.
In our latest project with x-ray fluorescence imaging we have scanned more than 50 pages of an ancient parchment book containing the work of the famous Greek physician, Galen of Pergamon. This so-called palimpsest contains a Syriac translation with his work including ‘On Simple Drugs’, which had been erased and overwritten with hymns in the Middle Ages, and catalogued as a new find at Saint Catherine’s Monastery in 1975. Scholars are interested in this translation as it gives information of how Galen’s work originally written in Greek spread east, were it became very popular in the Arab world. Using powerful synchrotron x-rays, we found that you can actually bring out this erased and overwritten text. And scholars can now read it! Key to this success was our new scanning system that records the whole x-ray fluorescence spectrum at each pixel of the image, and our collaborators’ ability to apply advanced machine learning algorithms to enhance the faint traces of overwritten text.
Another exciting project we are working on is an x-ray laser oscillator. There are currently five very big hard x-ray free electron lasers around the world, but they operate in a single pass, which means they are not very stable. Our idea is to use a train of pulses from one of these big x-ray lasers — those are the not-so-clean pulses — to pump our gain medium. After the first pulse creates amplified spontaneous emission, we guide the emitted beam through a cavity made of four mirrors back to the same gain medium to meet up with the next pump pulse from the train. Doing this again and again and again, lets us crank up the beam until we have a perfect, clean and stable x-ray laser pulse, and at the point we will send it out of the cavity. This is similar to how most optical lasers work. We described the idea in PNAS earlier this year, and now we have a lot of work ahead to turn it into reality.
What attracted you to UW–Madison?
For some time, I have been thinking whether it would be possible one day to combine my research activities with teaching at a university. The ultrafast x-ray science chair in the Physics Department was a perfect opportunity and an excellent fit to the research I have been pursuing my entire career. Still, it wasn’t until my visit to Madison, experiencing the wonderful interaction with the students, faculty and staff, and feeling the energy on this beautiful campus, that I fell in love with the idea of joining UW–Madison.
What is your favorite element and/or elementary particle?
Manganese is my favorite element, just because I have been spending so many years studying it and it has so many amazing properties. It’s chemically very important as it has all these different oxidation states, ranging from +2 to +7. And it’s at the heart of the tiny little machine driven by sun light that nature uses to split water into oxygen, which I think is the most important reaction on the planet. Without that reaction there would only be primitive bacterial life on earth. For the elementary particle, I feel almost ashamed but of course it has to be the electron, because it does all the work. Nuclei hardly notice any chemical change, but electrons do all the bonding, all the rearrangements that make the world run; they are the worker bees of nature.
What hobbies/other interests do you have?
I love nature, animals, music, and outdoor activities, especially in and around water.
High Energy Physics group awarded three grants totaling over $14 million
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HEP post-doc Dr. Camilla Galloni next to the CMS end cap supporting the GEM detectors that were installed this fall. The primary structure in this photo was engineered at the UW–Madison Physical Sciences Lab. The big CSC chambers were installed, upgraded and reinstalled and operated by UW physicists. The smaller GEM chambers, which are barely visible in the interstices, are being commissioned by UW–Madison physicists through the second grant mentioned in this post.
The High Energy Physics (HEP) group at UW–Madison, which broadly focuses on identifying and understanding the fundamental aspects of particles and forces in Nature, has been awarded three significant grants in 2020. The grants — two from the Department of Energy (DOE) and one from the National Science Foundation (NSF) — are awarded either directly to UW–Madison or indirectly through multi-institution international collaborations, bringing over $14 million to the department.
The first grant, $7.37 million from DOE, funds research that is expected to help physicists understand how our Universe works at its most fundamental level. At UW–Madison, this research includes experimental and theoretical studies into topics such as using the Higgs boson as a tool for new discoveries and identifying principles of dark matter.
The grant will fund five areas of research: 1) studies of high energy proton-proton collisions; 2) studies of neutrino interactions; 3) studies of super-weak signals from galactic dark matter particles; 4) wide-area imaging surveys using powerful new telescopes; and 5) computational and mathematical methods of quantum field theory and string theory.
The other two grants awarded will provide funding for upgrades to the Compact Muon Solenoid (CMS) project at the Large Hadron Collider (LHC) at CERN. The first is an NSF-funded grant for which Kevin Black is leading the UW–Madison effort to upgrade the CMS End Cap muon system upgrade. The $900,000 to the department is part of a larger multi-institutional grant through Cornell University and runs through 2025.
“The GEM detectors are novel micropattern gas detectors which can handle the high background rates expected in the end-cap muon detectors. They will enhance the triggering and reconstruction of forward muons which are expected to make significant improvements and increased acceptance to search for new particles and make precision measurements of known particles and interactions,” Black explains. “UW has a long history with CMS muon system with Prof Matt Herndon, Senior Emeritus Scientist Dick Loveless, and Senior Scientist Armando Lanaro leading to the design, construction, operation, and upgrade of the other end-cap subdetector system instrumented with Cathode Strip Chambers.”
The other CMS-specific grant is a four-year, $5.3 million DOE grant through Fermilab that will fund the CMS trigger upgrade. This funding will allow the UW–Madison CMS group to perform all aspects of the work involved in design, prototyping, qualification, production and validation of the calorimeter trigger system for the upgrade. When completed, the project is expected to result in the collection of 25 times more data than is currently possible. Sridhara Dasu is the principal investigator of this grant.
Surprising communication between atoms could improve quantum computing
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In their experiments, UW–Madison physicists led by Deniz Yavuz immobilized a group of rubidium atoms by laser-cooling them to just slightly above absolute zero. Then, they shined a laser at rubidium’s excitation wavelength to energize electrons. PHOTO COURTESY OF YAVUZ LAB
A group of University of Wisconsin–Madison physicists has identified conditions under which relatively distant atoms communicate with each other in ways that had previously only been seen in atoms closer together — a development that could have applications to quantum computing.
The physicists’ findings, published Oct. 14 in the journal Physical Review A, open up new prospects for generating entangled atoms, the term given to atoms that share information at large distances, which are important for quantum communications and the development of quantum computers.
“Building a quantum computer is very tough, so one approach is that you build smaller modules that can talk to each other,” says Deniz Yavuz, a UW–Madison physics professor and senior author of the study. “This effect we’re seeing could be used to increase the communication between these modules.”
Deniz Yavuz
The scenario at hand depends on the interplay between light and the electrons that orbit atoms. An electron that has been hit with a photon of light can be excited to a higher energy state. But electrons loathe excess energy, so they quickly shed it by emitting a photon in a process known as decay. The photons atoms release have less energy than the ones that boosted the electron up — the same phenomenon that causes some chemicals to fluoresce, or some jellyfish to have a green-glowing ring.
“Now, the problem gets very interesting if you have more than one atom,” says Yavuz. “The presence of other atoms modifies the decay of each atom; they talk to each other.”
The J.J. Sakurai Prize is considered one of the most prestigious annual prizes in the field of theoretical high energy physics. Barger, who joined the UW–Madison faculty in 1965, is a world leader in theoretical particle physics where theory meets experiment. He is one of the founders of collider phenomenology as it is practiced today.
“This prize belongs to the hundreds of students, postdocs, faculty and visiting colleagues who entered the portal of UW–Madison to discover the quarks, leptons and bosons of particle physics,” Barger says. “Only at UW–Madison could this research at the interface of theory and experiment so thrive.”
The techniques that Barger helped develop have been crucial in establishing the experimental foundations of the Standard Model of particle physics and in guiding the search for signals of new physics. His contributions have played a key role in many important milestones in particle physics, including the discovery of the W boson in 1985, the top quark in 1995, and the Higgs boson discovery in 2012.
UW–Madison physics professor Lisa Everett and University of Hawaii professor Xerxes Tata, both phenomenologists, co-nominated Barger for the prize.
“We are thrilled that Vernon Barger has been awarded the 2021 J.J. Sakurai Prize, for which we nominated him for his seminal accomplishments and leadership record in collider physics phenomenology over five decades in the field,” Everett says. “The techniques he has pioneered have and continue to be of pivotal importance for elucidating physics signals at particle colliders, and these contributions are only part of a very long and distinguished research career in theoretical particle physics. He is highly deserving of this honor.”
UW–Madison chemistry professor Martin Zanni also won an APS award, the Earle K. Plyler Prize for Molecular Spectroscopy & Dynamics. Read the UW–Madison news piece about both Barger and Zanni’s awards here.
Robert McDermott elected Fellow of the American Physical Society
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Robert McDermott
Congratulations to Prof. Robert McDermott, who was elected a 2020 Fellow of the American Physical Society! He was elected for seminal contributions to quantum computing with superconducting qubits, including elucidating the origins of decoherence mechanisms, and development of new qubit control and readout methods. He was nominated by the Division of Quantum Information.
APS Fellowship is a distinct honor signifying recognition by one’s professional peers for outstanding contributions to physics. Each year, no more than one half of one percent of the Society’s membership is recognized by this honor.
Massive halo finally explains stream of gas swirling around the Milky Way
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The Large and Small Magellanic Clouds as they would appear if the gas around them was visible to the naked eye. | Credits: Scott Lucchini (simulation), Colin Legg (background)
The Large and Small Magellanic Clouds are satellite galaxies of the Milky Way. They are surrounded by a high-velocity gaseous structure called the Magellanic Stream, which consists of gas stripped from both clouds. So far, simulations have been unable to reconcile observations with a complete picture of how the stream was formed. In this Nature week’s issue, numerical simulations carried out at by Scott Lucchini, graduate student at the Physics Department working with Elena D’Onghia, present a model that potentially resolves this conundrum. By embedding the Large Magellanic Cloud in a corona of ionized gas, the researchers were able to simulate the Magellanic Stream accurately and explain its structure. Ellen Zweibel and Chad Bustard are also co-authors of the article.
WQI team named winners in international quantum research competition
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A WQI faculty team was one of 18 winners in the Innovare Advancement Center’s “Million Dollar International Quantum U Tech Accelerator” competition, which awarded a total of $1.35 million last week. The winning teams, including UW–Madison physics professors Shimon Kolkowitz and Mark Saffman, each earned $75,000 toward their proposed research.
The competition attracted nearly 250 proposals from teams across the world in the areas of quantum timing, sensing, computing and communications, and 36 teams were invited to present at the live virtual event.
Prof. Brian Rebel promoted to Senior Scientist at Fermilab
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Brian Rebel
Yesterday, Fermilab promoted Prof. Brian Rebel to Senior Scientist. He has a joint appointment there, and his new title at Fermilab is the closest equivalent to full professor for which scientific staff are eligible. Congrats, Brian!
Q-NEXT collaboration awarded National Quantum Initiative funding
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The University of Wisconsin–Madison solidified its standing as a leader in the field of quantum information science when the U.S. Department of Energy (DOE) and the White House announced the Q-NEXT collaboration as a funded Quantum Information Science Research Center through the National Quantum Initiative Act. The five-year, $115 million collaboration was one of five Centers announced today.
Q-NEXT, a next-generation quantum science and engineering collaboration led by the DOE’s Argonne National Laboratory, brings together nearly 100 world-class researchers from three national laboratories, 10 universities including UW–Madison, and 10 leading U.S. technology companies to develop the science and technology to control and distribute quantum information.
“The main goals for Q-NEXT are first to deliver quantum interconnects — to find ways to quantum mechanically connect distant objects,” says Mark Eriksson, the John Bardeen Professor of Physics at UW–Madison and a Q-NEXT thrust lead. “And next, to establish a national resource to both develop and provide pristine materials for quantum science and technology.”
Mark Eriksson
Q-NEXT will focus on three core quantum technologies:
Communication for the transmission of quantum information across long distances using quantum repeaters, enabling the establishment of “unhackable” networks for information transfer
Sensors that achieve unprecedented sensitivities with transformational applications in physics, materials, and life sciences
Processing and utilizing “test beds” both for quantum simulators and future full-stack universal quantum computers with applications in quantum simulations, cryptanalysis, and logistics optimization.
Eriksson is leading the Materials and Integration thrust, one of six Q-NEXT focus areas that features researchers from across the collaboration. This thrust aims to: develop high-coherence materials, including for silicon and superconducting qubits, which is an essential component of preserving entanglement; develop a silicon-based optical quantum memory, which is important in developing a quantum repeater; and improve color-center quantum bits, which are used in both communication and sensing.
“One of the key goals in Materials and Integration is to not just improve the materials but also to improve how you integrate those materials together so that in the end, quantum devices maintain coherence and preserve entanglement,” Eriksson says. “The integration part of the name is really important. You may have a material that on its own is really good at preserving coherence, yet you only make something useful when you integrate materials together.”
“I’m excited about Q-NEXT because of the connections and collaborations it provides to national labs, other universities, and industry partners,” Eriksson says. “When you’re talking about research, it’s those connections that often lead to the breakthroughs.
The potential impacts of Q-NEXT research include the creation of a first-ever National Quantum Devices Database that will promote the development and fabrication of next generation quantum devices as well as the development of the components and systems that enable quantum communications across distances ranging from microns to kilometers.
“This funding helps ensure that the Q-NEXT collaboration will lead the way in future developments in quantum science and engineering,” says Steve Ackerman, UW–Madison vice chancellor for research and graduate education. “Q-NEXT is the epitome of the Wisconsin Idea as we work together to transfer new quantum technologies to the marketplace and support U.S. economic competitiveness in this growing field.”