Scientists Say Farewell to Daya Bay Site

The Daya Bay Reactor Neutrino Experiment collaboration – which made a precise measurement of an important neutrino property eight years ago, setting the stage for a new round of experiments and discoveries about these hard-to-study particles – has finished taking data. Though the experiment is formally shutting down, the collaboration will continue to analyze its complete dataset to improve upon the precision of findings based on earlier measurements.

The detectors for the Daya Bay experiment were built at UW–Madison by the Physical Sciences Laboratory, and detailed in a 2012 news release.

Says PSL’s Jeff Cherwinka, U.S. chief project engineer for Daya Bay:

The University of Wisconsin Physics Department and the Physical Sciences Lab were very involved in the design, fabrication and installation of the anti-neutrino detectors for the Daya Bay Experiment.  It was a great opportunity for faculty, staff, and students to participate in an important scientific measurement, while learning about another country and culture.  There were many trips and man years of effort in China by UW physicists, engineers and technicians to construct the experiment and many more for operations and data taking.  This international collaboration took a lot of effort, and in the end produced great results.

The chief experimentalist at UW–Madison was Karsten Heeger who has since left for Yale. At present, Prof. Baha Balantekin is the only one remaining at UW–Madison in the Daya Bay Collaboration.

A completion ceremony will be held Friday, December 11from 7:30-8:3opm CST. Video stream options and the full story can be found at Berkeley Lab’s website.

Researchers awarded Department of Energy Quantum Information Science Grant

Three UW–Madison physics professors and their colleagues have been awarded a U.S. Department of Energy (DOE) High Energy Physics Quantum Information Science award for an interdisciplinary collaboration between theoretical and experimental physicists and experts on quantum algorithms.

The grant, entitled “Detection of dark matter and neutrinos enhanced through quantum information,” will bring a total of $2.3 million directly to UW-Madison. Physics faculty include principal investigator Baha Balantekin as well as Mark Saffman, and Sue Coppersmith. Collaborators on the grant include Kim Palladino at the University of Oxford, Peter Love at Tufts University, and Calvin Johnson at San Diego State University.

With the funding, the researchers plan to use a quantum simulator to calculate the detector response to dark matter particles and neutrinos. The simulator to be used is an array of 121 neutral atom qubits currently being developed by Saffman’s group. Much of the research plan is to understand and mitigate the behavior of the neutral atom array so that high accuracy and precision calculations can be performed. The primary goal of this project is to apply lessons from the quantum information theory in high energy physics, while a secondary goal is to contribute to the development of quantum information theory itself.

Mark Friesen promoted to Distinguished Scientist

profile photo of Mark Friesen
profile photo of Mark Friesen
Mark Friesen

Congratulations to Mark Friesen on his promotion to Distinguished Scientist! The distinguished title is the highest title available to an academic staff member at UW–Madison.

Friesen joined the physics department in 2004 as an associate scientist, and has been with UW–Madison since 1998, when he began a postdoc in the Materials Sciences and Engineering department. His main research effort at UW–Madison has been related to silicon quantum dot quantum computing, in collaboration with physics professors Mark Eriksson, Sue Coppersmith, Bob Joynt, Maxim Vavilov, and others.

Friesen says his most important achievement in the department is serving as a research advisor: In 16 years with UW–Madison physics, he has advised or co-advised six postdocs, 11 Ph.D. theses, four current Ph.D. students, two M.S. theses, and several undergraduate research projects. He also has 123 peer-reviewed publications and five U.S. patents, and serves as a consultant for ColdQuanta, a quantum computing company.

“Mark is known around the world for his expertise in semiconductor-based quantum computing,” Mark Eriksson says. “He is especially well known for his calculations on how the band structure in silicon interacts with interfaces to determine the quantum states for electrons in silicon-based quantum devices.”

Congrats, Mark Friesen, on this well-deserved honor!

Welcome, Professor Uwe Bergmann!

profile image of Uwe Bergmann
profile photo of Uwe Bergmann
Uwe Bergmann

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

a woman in a helmet wearing a disposable facemask stands in front of lots of metal hardware and wires
a woman in a helmet wearing a disposable facemask stands in front of lots of metal hardware and wires
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.

Sridhara Dasu is principal investigator on this DOE grant. Co-investigators include Yang Bai, Vernon Barger, Keith Bechtol, Kevin Black, Tulika Bose, Lisa Everett, Matthew Herndon, Kimberly Palladino, Brian Rebel, Gary Shiu, Jennifer Thomas (WIPAC), and Sau Lan Wu. The grant was awarded in June 2020 and provides funding through March 2023.

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.

Ellen Zweibel elected AAAS Fellow

Congrats to Astronomy and Physics professor Ellen Zweibel on her election as a Fellow of the American Association for the Advancement of Science. She was elected “for distinguished contributions to quantify the role of magnetic fields in shaping the cosmos on all scales.” Read the full story about all six UW–Madison faculty who earned this honor.

Cary Forest, Jay Anderson, and John Wallace part of WARF Innovation Awards finalist team

profile photo of Cary Forest

Each fall the WARF Innovation Awards recognize some of the best of inventions at UW-Madison.

WARF receives hundreds of new invention disclosures each year. Of these disclosures, the WARF Innovation Award finalists are considered exceptional in the following criteria:


  • Has potential for high long-term impact
  • Presents an exciting solution to a known important problem
  • Could produce broad benefits for humankind

Cary Forest, Jay Anderson, and John Wallace are part of one of six finalists teams selected by WARF for their disclosure, “High-Energy Plasma Generator for Medical Isotope Production, Nuclear Waste Disposal & Power Generation.” Watch Video

Two Innovation Award winners will receive $10,000, split among UW inventors, and will be named at a virtual ceremony December 8. Learn more and register for the event.

See all six finalists and watch their videos at WARF’s Innovation Awards website.

Jimena González named Three Minute Thesis® finalist

Congrats to Jimena González, a physics graduate student in Keith Bechtol’s group, who is one of nine finalists for UW–Madison’s Three Minute Thesis® competition! Watch Jimena’s video on YouTube, and check out all nine finalists’ videos at the UW–Madison 3MT® website. The videos are only available through November 29. The finals will be held on February 3, 2021.

a still from a YouTube video of Jimena giving a presentation
Jimena González presents a virtual 3MT

A better understanding of coral skeleton growth suggests ways to restore reefs

Coral reefs are vibrant communities that host a quarter of all species in the ocean and are indirectly crucial to the survival of the rest. But they are slowly dying — some estimates say 30 to 50 percent of reefs have been lost — due to climate change.

In a new study, University of Wisconsin–Madison physicists observed reef-forming corals at the nanoscale and identified how they create their skeletons. The results provide an explanation for how corals are resistant to acidifying oceans caused by rising carbon dioxide levels and suggest that controlling water temperature, not acidity, is crucial to mitigating loss and restoring reefs.

“Coral reefs are currently threatened by climate change. It’s not in the future, it’s in the present,” says Pupa Gilbert, a physics professor at UW–Madison and senior author of the study. “How corals deposit their skeletons is fundamentally important to assess and help their survival.”

Read the Full Story | Link to the PNAS study