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Theoretical physicist Bernice Durand was a leader of gender equity on campus and in her field

Posted on February 22, 2022

Bernice Durand

Bernice Durand, Professor Emerita and one of the first two female professors in the UW–Madison Department of Physics, passed away February 7.

Durand was a theoretical physicist who specialized in particle theory and mathematical physics. Her research was on symmetry relations in algebra and physics, plus the phenomenology of high-energy interactions at large particle accelerators. She earned her BS and PhD degrees in physics from Iowa State University. In 1970, she started at UW–Madison as a research associate and lecturer and joined the faculty in 1977, where she directed nine PhD and three MS students.

As the first Associate Vice Chancellor for Diversity & Climate, Professor Durand provided leadership to ensure that faculty, staff, and student diversity issues including race, ethnicity, gender, sexual preference, and classroom and general campus workplace climate issues be addressed, and that search committees for non-classified staff be trained in broadening the pool of applicants and eliminating implicit bias. Durand co-directed a grant from the Alfred P. Sloan Foundation to the UW System designed to create more equity, flexibility and career options for faculty and academic staff. She was also a member of the leadership team of the Women in Science and Engineering Leadership Institute sponsored by the National Science Foundation to increase the participation and status of women in science.

A recipient of the Chancellor’s Award for Outstanding Teaching, Professor Durand taught courses at all levels, from modern physics for non-scientists (“Physics for Poets”) to a specialized course she developed for advanced graduate students in the use of topology and algebra in quantum field theory. In the mid-1990s, she used technological and pedagogical techniques in her teaching, such as broadcasting her modern physics for non-scientists course on public television with web-based coursework and pioneering one of two early versions of MOOCs (massive open online courses) on campus.

The department announced the annual Bernice Durand Undergraduate Research Scholarship in 2003, which gives preference to students from underrepresented groups in Physics and Astronomy who show research potential, motivation, and interest in the discipline. In 2018, the department’s Board of Visitors sought to create an endowed faculty fund in honor of Durand. Thanks to generous support from several Board of Visitors members and Bernice’s husband, Professor Emeritus Randy Durand, the Bernice Durand Faculty Fellowship was established in 2021. The Department plans to use the Durand Faculty Fellowship to support a professor in the department who will expand efforts to create a more diversified faculty.

Bernice is survived by her husband, Loyal Durand, also a UW–Madison Professor Emeritus of Physics; by stepsons Travis, Tim, and Chris Durand, whom she helped to raise from early ages; and by five nieces and nephews.

Read the Wisconsin State Journal’s Obituary
Visit the Department Tribute Page

Ultraprecise atomic clock poised for new physics discoveries

Posted on February 16, 2022

University of Wisconsin–Madison physicists have made one of the highest performance atomic clocks ever, they announced Feb. 16 in the journal Nature.

Their instrument, known as an optical lattice atomic clock, can measure differences in time to a precision equivalent to losing just one second every 300 billion years and is the first example of a “multiplexed” optical clock, where six separate clocks can exist in the same environment. Its design allows the team to test ways to search for gravitational waves, attempt to detect dark matter, and discover new physics with clocks.

“Optical lattice clocks are already the best clocks in the world, and here we get this level of performance that no one has seen before,” says Shimon Kolkowitz, a UW–Madison physics professor and senior author of the study. “We’re working to both improve their performance and to develop emerging applications that are enabled by this improved performance.”

Atomic clocks are so precise because they take advantage of a fundamental property of atoms: when an electron changes energy levels, it absorbs or emits light with a frequency that is identical for all atoms of a particular element. Optical atomic clocks keep time by using a laser that is tuned to precisely match this frequency, and they require some of the world’s most sophisticated lasers to keep accurate time.

By comparison, Kolkowitz’s group has “a relatively lousy laser,” he says, so they knew that any clock they built would not be the most accurate or precise on its own. But they also knew that many downstream applications of optical clocks will require portable, commercially available lasers like theirs. Designing a clock that could use average lasers would be a boon.

Read the full story

Shimon Kolkowitz one of four UW professors awarded Sloan Fellowship

Posted on February 16, 2022

Four University of Wisconsin–Madison professors, including assistant professor of physics Shimon Kolkowitz, have been named to Sloan Research Fellowships — competitive, prestigious awards given to promising researchers in the early stages of their careers.

“Today’s Sloan Research Fellows represent the scientific leaders of tomorrow,” says Adam F. Falk, president of the Alfred P. Sloan Foundation, which has awarded the fellowships since 1955. “As formidable young scholars, they are already shaping the research agenda within their respective fields—and their trailblazing won’t end here.”

Kolkowitz, an assistant professor of physics, builds some of the most precise clocks in the world by trapping ultracold atoms of strontium — clocks so accurate they could be used to test fundamental theories of physics and search for dark matter.

UW–Madison’s other 2022 Sloan Fellows are Tatyana Shcherbina (math), Zachary K. Wickens (chemistry) and Andrew Zimmer (math).

The UW–Madison professors are among 118 researchers from the United States and Canada honored by the New York-based philanthropic foundation. The four new fellows join 110 UW–Madison researchers honored in the past.

Each fellow receives $75,000 in research funding from the foundation, which awards Sloan Research Fellowships in eight scientific and technical fields: chemistry, computer science, economics, mathematics, computational and evolutionary molecular biology, neuroscience, ocean sciences and physics.

Physics of Climate Change project funded by WI Idea grant

Posted on February 14, 2022

Eleven research projects that illustrate how the Wisconsin Idea has evolved — including one from the Department of Physics — have now been funded by Extension and the Office of the Vice Chancellor for Research and Graduate Education.

The premise of the Wisconsin Idea, extending university knowledge to all corners of the state, is traditionally described as starting on campus and traveling to other parts of Wisconsin. This new series of grant-funded projects recognizes the value of knowledge transfer in reverse: utilizing Extension’s local networks to bring community perspectives and knowledge into research studies conducted on campus.

The Wisconsin Idea is almost 120 years old, and in that time it has evolved to include the wide range of topics currently being studied by faculty and specialists at UW–Madison. Extension’s locally based educators deliver evidence-based programming for farmers and 4-H youth and also help address specific issues in local communities by sharing expertise on natural resources, family, financial, economic development, and health/well-being topics.

The heart of the Wisconsin Idea – creating vital links between UW–Madison and communities across the state to inform community programming and improve lives – is embodied as the core mission of Extension. The new grant series will showcase how communities can both inform and benefit from university research. This work follows the longstanding tradition of Extension’s role to advance the Wisconsin Idea, while the research methods used to develop knowledge continue to evolve.

Extension collaborated with the Office of the Vice Chancellor for Research and Graduate Education to create the Wisconsin Idea Collaboration Grant project series. The competitive grants will kickstart applied research and development of innovative educational programming or community engagement to address community needs and priorities.

Funded project: The Physics of Climate Change

Principal Investigator Mallory Conlon (Physics); co-PIs Cierra Atkinson (Physics), Haddie McLean (Physics), and Joanna Skluzacek, Professor and STEM Specialist, Division of Extension

The scientific principles explaining and predicting the effects of climate change are being lost in the noise of rampant misinformation. Understanding of climate change varies across age groups and location, and many K-12 teachers are left without the support needed to incorporate climate change concepts in their curricula.

To mitigate misinformation, this project will create hands-on activities to understand the impacts of climate change and empower teachers to accurately share content with their students. Specific efforts will include a museum exhibit at the Ingersoll Physics Museum, outreach demonstration for the Wonders of Physics traveling show, and an activity kit designed to empower middle and high school students, teachers, and general audiences to identify accurate information about climate change.

Maxim Vavilov named Vilas Associate

Posted on February 3, 2022

The Office of the Vice Chancellor for Research and Graduate Education has announced 26 faculty winners of the Vilas Associates Competition, including physics professor Maxim Vavilov. The competition recognizes “new and ongoing research of the highest quality and significance.” Tenure-track assistant professors and tenured faculty within 20 years of their tenure date are eligible.

The award is funded by the William F. Vilas Estate Trust.

Recipients are chosen competitively by the divisional research committees on the basis of a detailed proposal. Winners receive up to two-ninths of research salary support (including the associated fringe costs) for the summers of 2022 and 2023, as well as a $12,500 flexible research fund in each of the two fiscal years. Faculty paid on an annual basis are not eligible for the summer salary support but are eligible for the flexible fund portion of this award.

Coral skeleton formation rate determines resilience to acidifying oceans

Posted on January 27, 2022

A new University of Wisconsin–Madison study has implications for predicting coral reef survival and developing mitigation strategies against having their bony skeletons weakened by ocean acidification.

Though coral reefs make up less than one percent of the ocean floor, these ecosystems are among the most biodiverse on the planet — with over a million species estimated to be associated with reefs.

The coral species that make up these reefs are known to be differently sensitive or resilient to ocean acidification — the result of increasing atmospheric carbon dioxide levels. But scientists are not sure why.

In the study, researchers show that the crystallization rate of coral skeletons differs across species and is correlated with their resilience to acidification.

A woman holding two coral species stands in front of a body of water — “Finding solutions that are science-based is a priority,” says physics professor Pupa Gilbert, shown here with samples of scleractinian coral along the Lake Monona shoreline in Madison. | *Photo: Jeff Miller*

“Many agencies keep putting out reports in which they say, ‘Yes, coral reefs are threatened,’ with no idea what to do,” says Pupa Gilbert, a physics professor at UW–Madison and senior author of the study that was published Jan. 17 in the Journal of the American Chemical Society. “Finding solutions that are science-based is a priority, and having a quantitative idea of exactly what’s happening with climate change to coral reefs and skeletons is really important.”

Reef-forming corals are marine animals that produce a hard skeleton made up of the mostly insoluble crystalline material aragonite. Aragonite forms when precursors made up of a more soluble form, amorphous calcium carbonate, are deposited onto the growing skeleton and then crystallize.

The team studied three genera of coral and took an in-depth look at the components of their growing skeletons. They used a technique that Gilbert pioneered called PEEM spectromicroscopy, which detects the different forms of calcium carbonate with the greatest sensitivity to date.

When they used these spectromicroscopy images to compare the thickness of amorphous precursors to the crystalline form, they found that Acropora, which is more sensitive to acidification, had a much thicker band of amorphous calcium carbonate than Stylophora, which is less sensitive.

A third genus of unknown sensitivity, Turbinaria, had an even thinner amorphous precursor layer than Stylophora, suggesting it should be the most resilient of the three to ocean acidification.

two bright colored images assign a color to the form of calcium present in coral skeletons. On the left there is a thicker band of non-blue (blue is crystalline aragonite) compared to the image on the right where there is almost all blue, indicating the skeleton on the right crystallizes to aragonite more quickly — Coral skeletons were studied with PEEM spectromicroscopy, which identifies the calcium spectrum associated with each imaging pixel, then renders it in false color depending on the form of calcium. Blue is aragonite, the insoluble, crystalline form of calcium carbonate; the other colors represent one of the two amorphous precursor forms, a mix of the two, or a mix of aragonite and precursor form. Acropora spp. (left), has more non-blue pixels compared to Turbinaria spp. (right), indicating that Acropora has more of the soluble, non-crystalline form in its growing skeleton. | *Pupa Gilbert and team in JACS*

The thicker the band of uncrystallized minerals, the slower the crystallization process.

“If the surface of the coral skeleton, where all this amorphous calcium carbonate is being deposited by the living animal, crystallizes quickly, then that particular species is resilient to ocean acidification; if it crystallizes slowly, then it’s vulnerable,” Gilbert says. “For once, it’s a really simple mechanism.”

The mechanism may have worked out to be simple, but the data analysis required to process and interpret the PEEM images is anything but. Each pixel of imaging data acquired has a calcium spectrum that needs to be analyzed, which results in millions of data points. Processing the data includes many decision-making points, plus massive computing power.

The team has tried to automate the analysis or use machine-learning techniques, but those methods have not worked out. Instead, Gilbert has found that humans making decisions are the best data processors.

Gilbert did not want to base conclusions off the decision-making of just one or two people. So she hired a group of UW–Madison undergraduates, most of whom came from the Mercile J. Lee Scholars Program, which works to attract and retain talented students from underrepresented groups. This team provided a large and diverse group of decision makers.

a zoom screen showing several of the people who conducted the study — Gilbert and her research team met several times a week via Zoom, where students were assigned the same dataset to process in parallel and discuss at their next meeting. The Cnidarians — named after the phylum to which corals belong — include current and former UW–Madison undergraduates: Celeo Matute Diaz, Jorge Rivera Colon, Asiya Ahmed, Virginia Quach, Gabi Barreiro Pujol, Isabelle LeCloux, Sydney Davison, Connor Klaus, Jaden Sengkhamee, Evan Walch and Benjamin Fordyce; and graduate students Cayla Stifler, and Connor Schmidt. Schmidt was also the lead author of the study. | *Provided by Pupa Gilbert*

Dubbed the Cnidarians — from the phylum to which corals, anemones and jellyfish belong — this group of students became integral members of the team. They met several times a week via Zoom, when Gilbert would assign multiple students the same dataset to process in parallel and discuss at their next meeting.

“If multiple people come up with precisely the same solution even though they make different decisions, that means our analysis is robust and reliable,” Gilbert says. “The Cnidarians’ contributions were so useful that 13 of them are co-authors on this study.”

THIS STUDY WAS SUPPORTED BY THE DEPARTMENT OF ENERGY (DE-FG02-07ER15899 AND DE-AC02-05CHH11231), THE NATIONAL SCIENCE FOUNDATION (DMR-1603192) AND THE EUROPEAN RESEARCH COUNCIL (755876).

Alex Levchenko named Humboldt Fellow

Posted on January 7, 2022

UW–Madison physics professor Alex Levchenko has been named a Humboldt Fellow for Experienced Researchers. Sponsored by the Alexander von Humboldt Foundation, the fellowship enabled highly-qualified scientists and scholars from abroad to spend time conducting research at a partner university in Germany.

Levchenko was nominated by the Max Planck Institute for Solid State Research in Stuttgart, where he will be affiliated with the Quantum Many Body Theory Department. His research topic will be “Effects of Strong Coupling Fluctuations, Criticality, and Topology in Superconductors.”

Machine Learning meets Physics

Posted on December 17, 2021

Machine learning and artificial intelligence are certainly not new to physics research — physicists have been using and improving these techniques for several decades.

In the last few years, though, machine learning has been having a bit of an explosion in physics, which makes it a perfect topic on which to collaborate within the department, the university, and even across the world.

“In the last five years in my field, cosmology, if you look at how many papers are posted, it went from practically zero to one per day or so,” says assistant professor Moritz Münchmeyer. “It’s a very, very active field, but it’s still in an early stage: There are almost no success stories of using machine learning on real data in cosmology.”

Münchmeyer, who joined the department in January, arrived at a good time. Professor Gary Shiu was a driving force in starting the virtual seminar series “Physics ∩ ML” early in the pandemic, which now has thousands of people on the mailing list and hundreds attending the weekly or bi-weekly seminars by Zoom. As it turned out, physicists across fields were eager to apply their methods to the study of machine learning techniques.

“So it was natural in the physics department to organize the people who work on machine learning and bring them together to exchange ideas, to learn from each other, and to get inspired,” Münchmeyer says. “Gary and I decided to start an initiative here to more efficiently focus department activities in machine learning.”

Currently, that initiative includes Münchmeyer, Shiu, Tulika Bose, Sridhara Dasu, Matthew Herndon, and Pupa Gilbert, and their research group members. They watch the Physics ∩ ML seminar together, then discuss it afterwards. On weeks that the virtual seminar is not scheduled, the group hosts a local speaker — from physics or elsewhere on campus — who is doing work in the realm of machine learning.

In the next few years, the Machine Learning group in physics looks to build on the momentum the field currently has. For example, they hope to secure funding to hire postdoctoral fellows who can work within a group or across groups in the department. Also, the hiring of Kyle Cranmer — one of the best-known researchers in machine learning for physics — as Director of the American Family Data Science Institute and as a physics faculty member, will immediately connect machine learning activities in this department with those in computer sciences, statistics, and the Information School, as well other areas on campus.

“There are many people [on campus] actively working on machine learning for the physical sciences, but there was not a lot of communication so far, and we are trying to change that,” Münchmeyer says.

Machine Learning Initiatives in the Department (so far!)

Kevin Black, Tulika Bose, Sridhara Dasu, Matthew Herndon and the CMS collaboration at CERN use machine learning techniques to improve the sensitivity of new physics searches and increase the accuracy of measurements.

Pupa Gilbert uses machine learning to understand patterns in nanocrystal orientations (detected with her synchrotron methods) and fracture mechanics (detected at the atomic scale with molecular dynamics methods developed by her collaborator at MIT).

Moritz Münchmeyer develops machine learning techniques to extract information about fundamental physics from the massive amount of complicated data of current and upcoming cosmological surveys.

Gary Shiu develops data science methods to tackle computationally complex systems in cosmology, string theory, particle physics, and statistical mechanics. His work suggests that Topological Data Analysis (TDA) can be integrated into machine learning approaches to make AI interpretable — a necessity for learning physical laws from complex, high dimensional data.

Shimon Kolkowitz earns NSF CAREER award

Posted on December 15, 2021

Shimon Kolkowitz

Shimon Kolkowitz has already developed one of the most precise atomic clocks ever. Now, the UW–Madison physics professor has been awarded a Faculty Early Career Development (CAREER) award from the National Science Foundation (NSF) to use his atomic clocks to potentially answer some big questions about the physics of our universe.

The five-year, $800,000 in total award will cover research expenses, graduate student support, and outreach projects based on the research.

“I am honored and proud to receive an NSF CAREER award, which will help my research group expand our experimental efforts and build upon our recent results,” Kolkowitz says. “This award will support research into new ways to harness the remarkable precision of optical atomic clocks for exciting physics applications such as searching for dark matter and detecting gravitational waves.”

Atomic clocks are so precise because they take advantage of the natural vibration frequencies of atoms, which are identical for all atoms of a particular element. Kolkowitz and his research group have developed atomic clocks that can detect the difference in these frequencies between two clocks that would only disagree with each other by one second after 300 billion years, the tiniest detectable frequency changes to date. These clocks, then, can measure effects that shifts their frequency by only 0.00000000000000001%, opening the possibility of using them in the search for new physics.

A significant advancement in Kolkowitz’s clocks is that they are multiplexed, with six or more separate clocks in one

vacuum chamber, effectively placing each clock in the same environment. Mutliplexing means that comparisons between the clocks, and not their individual accuracy, is what matters — and allows the group to use commercially available, robust and portable lasers in their measurements. Though the clocks are not yet ready to be used to detect gravitational waves, Kolkowitz says the current setup “looks a bit like how you would eventually do that,” and will allow him to test out and demonstrate the concept.

In the spirit of the Wisconsin Idea and the NSF’s “broader impacts” to benefit society beyond scientific merit, with this award, Kolkowitz will focus efforts on quantum science outreach with pre-college students.

“We’ll be developing new demos and hands-on activities designed to introduce K-12 students to modern physics concepts,” Kolkowitz says. “We’ll use these activities to engage students at live shows and interactive events as part of The Wonders of Physics outreach program, with an emphasis on reaching rural and Native American communities in Wisconsin.”

NSF established these awards to help scientists and engineers develop simultaneously their contributions to research and education early in their careers. CAREER funds are awarded by the federal agency to junior-level faculty at colleges and universities.

Bucket brigades and proton gates: Researchers shed new light on water’s role in photosynthesis

Posted on November 22, 2021

This story is adapted from one originally published by SLAC by Ali Sundermier

Photosystem II is a protein in plants, algae and cyanobacteria that uses sunlight to break water down into its atomic components, unlocking hydrogen and oxygen. A longstanding question about this process is how water molecules are funneled into the center of Photosystem II, where water is split to produce the oxygen we breathe. A better understanding of this process could inform the next generation of artificial photosynthetic systems that produce clean and renewable energy from sunlight and water.

In a paper published last week in Nature Communications, an international collaboration between scientists at the Department of Energy’s Lawrence Berkeley National Laboratory (LBNL), SLAC National Accelerator Laboratory and several other institutions uncovers how the protein takes in water and how hydrogen is removed in order to release the oxygen molecules.

Uwe Bergmann

“Plants use the energy from sunlight to split two water molecules and produce the oxygen we breath. The study shows for the first time atomic-resolution snapshots of the likely channel and gate, where the water molecules arrive to the catalytic center to be split apart, and the channel where the protons are shuttled out during the splitting,” says Uwe Bergmann, the Martin L. Perl professor in ultrafast x-ray science at UW–Madison. “This information will help our understanding of one of the most fundamental reactions on earth, and how we might use sunlight in the future to create fuels.”

At SLAC’s Linac Coherent Light Source (LCLS) X-ray laser, the team illuminated samples from cyanobacteria with ultrafast pulses of X-rays to collect both X-ray crystallography and spectroscopy data to simultaneously map the protein structure and how electrons flow in the protein. Through this technique, they are able to test competing theories of how Photosystem II splits water into oxygen. Over the past few years, the team has used this method to observe various steps of this water-splitting cycle at the temperature at which it occurs in nature.

Scientists at UW–Madison have been instrumental to developing these and related x-ray imaging methods over the last decade.

The center of the protein acts as a catalyst, which drives certain chemical reactions to happen in a highly efficient manner. This research seeks to unlock how nature has optimized this catalytic process over millions of years of evolution. A cluster of four manganese atoms and one calcium atom are connected by oxygen atoms, and surrounded by water and the outer layers of the protein. In the step the scientists looked at, water flows through a pathway into the center of the protein, where one water molecule ultimately forms a bridge between a manganese atom and a calcium atom. The researchers showed that this water molecule likely provides one of the oxygen atoms in the oxygen molecule produced at the end of the cycle.

a schematic of the proposed mechanism is shown — The proposed proton gate around D1-E65, D2-E312, and D1-R334 in the open and closed state. | In Nature Communications, https://doi.org/10.1038/s41467-021-26781-z

Last year, the researchers discovered that Photosystem II ferries water into the center as if through a bucket brigade: Water molecules move in many small steps from one end of the pathway to the other. They also showed that the calcium atom within the center could be involved in shuttling the water in. In this most recent study, the researchers pinpoint, for the first time, the exact pathway where this process unfolds.

“This might prevent water from interacting with the center prematurely, resulting in unwanted intermediates such as peroxide that can cause damage to the enzyme,” said Jan Kern, staff scientist at LBNL and one of the corresponding authors.

The researchers also showed that there is another pathway dedicated to removing hydrogen protons generated during the water-splitting reaction. In the proton pathway, they discovered the existence of a “proton gate,” which blocks the proton from coming back to the center.

“These results show where and how the water molecules enter the catalytic site, and where the protons are released, advancing our understanding of how two waters may come together to form the oxygen we breathe,” said Junko Yano, senior scientist at LBNL and one of the corresponding authors. “It demonstrates that it is just not enough to determine the structure of the main catalytic center, but it is also important to understand how the entire protein carries out the reaction.”

In addition to SLAC and LBNL, the collaboration includes researchers from Uppsala University in Sweden; Humboldt University of Berlin; and the University of Wisconsin-Madison.

LCLS is a DOE Office of Science user facility. This research was supported by the Office of Science.