Maxim Vavilov named Vilas Associate

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.

Alex Levchenko named Humboldt Fellow

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.”

Shimon Kolkowitz earns NSF CAREER award

profile photo of Shimon Kolkowitz
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.”

optical video of a ball of strontium atoms being mutliplexed into 6 separate, smaller spheres of atoms, like pearls along a string
From one sphere of supercooled strontium atoms, Kolkowitz’s group multiplexes them into six separate spheres, each of which can be used as an atomic clock.

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.

Study of high-energy particles leads PhD student Alex Wang to Department of Energy national lab

This story, by Meghan Chua, was originally published by the Graduate School

In 2012, scientists at CERN’s Large Hadron Collider announced they had observed the Higgs boson particle, verifying many of the theories of physics that rely on its existence.

profile photo of Alex Wang
Alex Wang

Since then, scientists have continued to search for the properties of the Higgs boson and for related particles, including an extremely rare case where two Higgs boson particles appear at the same time, called di-Higgs production.

“We’ve had some searches for di-Higgs right now, but we don’t see anything significant yet,” said Alex Wang, a PhD student in experimental high energy physics at UW­–Madison. “It could be because it doesn’t exist, which would be interesting. But it also could just be because, according to the Standard Model theory, it’s very rare.”

Wang will have a chance to aid in the search for di-Higgs production in more ways than one. Starting in November, he will spend a year at the SLAC National Accelerator Laboratory as an awardee in the Department of Energy Office of Science Graduate Student Research Program.

The program funds outstanding graduate students to pursue thesis research at Department of Energy (DOE) laboratories. Students work with a DOE scientist on projects addressing societal challenges at the national and international scale.

At the SLAC National Accelerator Laboratory, Wang will primarily work on hardware for a planned upgrade of the ATLAS detector, one of the many detectors that record properties of collisions produced by the Large Hadron Collider. Right now, ATLAS collects an already massive amount of data, including some events related to the Higgs boson particle. However, Higgs boson events are extremely rare.

In the future, the upgraded High-Luminosity Large Hadron Collider (HL-LHC) will enable ATLAS to collect even more data and help physicists to study particles like the Higgs boson in more detail. This will make it more feasible for researchers to look for extremely rare events such as di-Higgs production, Wang said. The ATLAS detector itself will also be upgraded to adjust for the new HL-LHC environment.

a black background with orange cones and small yellow box-like dots indicate the signal events
This image of a signal-like event in the ATLAS detector comes from one of the Higgs boson-related analyses Wang works on. The red cones and cyan towers indicate particles which may have originated from the decay of two Higgs boson particles. (Photo credit: ATLAS Experiment © 2021 CERN)

“I’m pretty excited to go there because SLAC is essentially where they’ll be assembling the innermost part of the ATLAS detector for the future upgrade,” Wang said. “So, I think it’s going to be a really central place in the future years, at least for this upgrade project.”

Increasing the amount of data a sensor collects can also cause problems, such as radiation damage to the sensors and more challenges sorting out meaningful data from background noise. Wang will help validate the performance of some of the sensors destined for the upgraded ATLAS detector.

“I’m also pretty excited because for the data analysis I’m doing right now, it’s mainly working in front of a computer, so it will be nice to have some experience working with my hands,” Wang said.

At SLAC, he will also spend time searching for evidence of di-Higgs production.

Wang’s thesis research at UW–Madison also revolves around the Higgs boson particle. He sifts through data from the Large Hadron Collider to tease out which events are “signals” related to the Higgs boson, versus events that are “backgrounds” irrelevant to his work.

One approach Wang uses is to predict how many signal events researchers expect to see, and then determine if the number of events recorded in the Large Hadron Collider is consistent with that prediction.

“If we get a number that’s consistent with our predictions, then that supports the existing model of physics that we have,” Wang said. “But for example, if you see that the theory predicts we’d have 10 events, but in reality, we see 100 events, then that could be an indication that there’s some new physics going on. So that would be a potential for discoveries.”

The Department of Energy formally approved the U.S. contribution to the High-Luminosity Large Hadron Collider accelerator upgrade project earlier this year. The HL-LHC is expected to start producing data in 2027 and continue through the 2030s. Depending on what the future holds, Wang may be able to use data from the upgraded ATLAS detector to find evidence of di-Higgs production. If that happens, he also will have helped build the machine that made it possible.

Physics has lots of winners in the Cool Science Image contest!

This story is largely adapted from UW’s announcement of the 2021 Cool Science Image contest winners.

Ten images and two videos created by University of Wisconsin–Madison students, faculty and staff — including two images from Physics and one from IceCube — have been named winners of the 2021 Cool Science Image Contest.

The winners from physics include Joel Siegel, Margaret Fortman, and Gregory Holdman; from IceCube, Yuya Makino.

A panel of nine experienced artists, scientists and science communicators judged the scientific content and aesthetic and creative qualities of scores of images and videos entered in the 11th annual competition. The winning entries showcase animals and plants, the invisibly small structures all around us, and stars and nebulae millions of millions of miles away.

An exhibit featuring the winners is open to the public at the McPherson Eye Research Institute’s Mandelbaum and Albert Family Vision Gallery on the ninth floor of the Wisconsin Institutes for Medical Research, 111 Highland Ave., through December. A reception — open to the public — for the contest entrants will be held at the gallery on Oct. 7 from 4:30 to 6:30 p.m.

Winning submissions were created with point-and-shoot digital cameras, cutting-edge microscopes, and telescopes of both the backyard and mountaintop variety.

Because sometimes, there’s no substitute for the visual.

“An image often can convey meaning more effectively than words,” says Ahna Skop, a longtime contest judge, artist and UW–Madison professor of genetics and active ambassador for science. “We know from marketing and education research that adding a picture with words to a slide increases retention of knowledge by 65 percent. The visual communication of science is critical for the transference of knowledge broadly.”

The winning entries from Physics/IceCube


greyscale abstract image of things that appear to look like 3D towers in the shape of snowflakes
By varying the exact size and shape of these micrometer-wide, star-shaped pillars etched into a silicon wafer, researchers can carefully manipulate light passing through a lens to correct for aberrations that would otherwise focus different wavelengths of light on different points in space. | Gregory Holdman, graduate student, Physics, focused ion beam and scanning electron microscope


image looks like a black and white maze
Mazes of tiny structures less than 15 billionths of a meter across and made of some of the smallest ribbons of graphene — layers of carbon just a single atom thick — ever fabricated represent an important step toward graphene-based telecommunications devices. | Joel Siegel and Margaret Fortman, graduate students, Physics; Jian Sun, graduate student, Materials Science; Jonathan Dwyer, PhD alumnus, Chemical Engineering, scanning electron microscope


a bundled up person in the snow with the neon green glow of an aurora overhead
A “winterover” — one of the two staff members who stay through the minus-100-degree Fahrenheit nights of Antarctica’s coldest months — hikes underneath the stars and aurora to the South Pole home of IceCube, a UW–Madison-led neutrino telescope frozen in a cubic kilometer of ice. | Yuya Makino, assistant scientist, IceCube Neutrino Observatory, digital camera

2021 Homi Bhabha Award given to Francis Halzen

This story was originally published by the IceCube collaboration.

profile photo of Francis Halzen
Francis Halzen | Image: Zig Hampel-Arias, WIPAC.

The International Union of Pure and Applied Physics (IUPAP) and the Tata Institute of Fundamental Research (TIFR) in Mumbai, India, have awarded the 2021 Homi Bhabha Medal and Prize to Francis Halzen, the Hilldale and Gregory Breit Distinguished Professor of Physics at the University of Wisconsin–Madison and principal investigator of IceCube, for his “distinguished contributions in the field of high-energy cosmic-ray physics and astroparticle physics over an extended academic career.” Halzen accepted the award at the opening session of the virtual 37th International Cosmic Ray Conference, on July 12, 2021.

The Bhabha Award was established by IUPAP and TIFR in 2010 to honor Dr. Homi Jehangir Bhabha, a cosmic ray physicist well known for the Bhabha-Heitler cascade theory and relativistic positron-electron scattering, also known as Bhabha scattering. Bhabha founded TIFR in 1945 and initiated the nuclear energy program in India in 1951. He initiated experimental programs for the study of cosmic ray particles and their interactions with instruments either carried aloft to the top of the atmosphere with balloons or placed in laboratories at high altitude or deep underground. The Homi Bhabha Medal and Prize consists of a certificate, a medal, a monetary award, and an invitation to visit the TIFR, Mumbai, and the Cosmic Ray Laboratory, Ooty to give public lectures. It is awarded biennially at the International Cosmic Ray Conference.

Born in Belgium, Halzen received his Master’s and PhD degrees from the University of Louvain, Belgium, and has been on the physics faculty at UW–Madison since 1972. The Bhabha Award is just the latest in Halzen’s long and storied career; previous accolades include a 2014 American Ingenuity Award, the 2015 Balzan Prize, a 2018 Bruno Pontecorvo Prize, the 2019 IUPAP Yodh Prize, and the 2021 Bruno Rossi Prize. Halzen is the third IceCube collaborator to win a Bhabha Award after Tom Gaisser in 2015 and Subir Sarkar in 2017.

During his virtual acceptance remarks, Halzen credited his collaborators, saying, “If I made contributions, it is because I ran into incredible collaborators who were leaders in the field, and still are. My ultimate collaborators, of course, I found within the AMANDA collaboration—and now IceCube—who made high-energy neutrinos part of the high-energy cosmic ray spectrum…

“Thanks to everybody, and thanks to IceCube; this prize is shared with all of you.”

Francis Halzen named Vilas Research Professor

Francis Halzen

UW–Madison physics professor Francis Halzen has been named a Vilas Research Professor. Created “for the advancement of learning,” Vilas Research Professorships are granted to faculty with proven research ability and unusual qualifications and promise. The recipients of the award have contributed significantly to the research mission of the university and are recognized both nationally and internationally.

Halzen, the Gregory Breit and Hilldale Professor of Physics, joined the UW­­–Madison faculty in 1972. He has made pioneering contributions to particle physics and neutrino astrophysics, and he continues to be the driving force of the international IceCube Collaboration.

Early in his career, Halzen cofounded the internationally recognized phenomenology research institute in the UW–Madison Department of Physics to promote research at the interface of theory and experiment in particle physics. This institute is recognized for this research and for its leadership in the training of postdocs and graduate students in particle physics phenomenology.

The IceCube Neutrino Observatory is the culmination of an idea first conceived in the 1960s, and one in which Halzen has played an integral role in its design, implementation, and data acquisition and analysis for the past three decades. After initial experiments confirmed that the Antarctic ice was ultratransparent and established the observation of atmospheric neutrinos, IceCube was ready to become a reality. From 2004 to 2011, the South Pole observatory was constructed — the largest project ever assigned to a university and one led by Halzen.

After two years of taking data with the full detector, the IceCube Neutrino Observatory opened a new window onto the universe with its discovery of highly energetic neutrinos of extragalactic origin. This discovery heralded the beginning of the exploration of the universe with neutrino telescopes. The IceCube observation of cosmic neutrinos was named the 2013 Physics World Breakthrough of the Year.

Nationally and internationally renowned for this work, Halzen was awarded a 2014 American Ingenuity Award, a 2015 Balzan Prize, a 2018 Bruno Pontecorvo Prize, a 2019 Yodh Prize, and a 2021 Bruno Rossi Prize.

With the Vilas Research Professorship, Halzen is also recognized for his commitment to education and service in the department, university, and international science communities. He has taught everything from physics for nonscience majors to advanced particle physics and special topics courses at UW–Madison. He has actively participated on several departmental and university committees as well as advisory, review, and funding panels. His input is highly sought by committees and agencies that assess future priorities of particle and astroparticle physics research.

“Francis Halzen has had a prolific, internationally recognized research career, has shown excellence as an educator who is able to effectively communicate cutting-edge science on all levels, and has made tireless and valued contributions in service of the department,” says Sridhara Dasu, Physics Department chair. “He is one of the most creative and influential physicists of the last half century and worthy of the prestigious Vilas Research Professorship.”

Vilas awards are supported by the estate of professor, U.S. senator and UW Regent William F. Vilas (1840-1908). The Vilas Research Professorship provides five years of flexible funding — two-thirds of which is provided by the Office of the Provost through the generosity of the Vilas trustees and one-third provided by the school or college whose dean nominated the winner.

Halzen joins department colleagues Profs. Vernon Barger and Sau Lan Wu as recipients of this prestigious UW–Madison professorship.

Ke Fang receives prestigious Shakti Duggal Award

This article was originally published by WIPAC

Ke Fang, professor at the University of Wisconsin–Madison, has been selected as the recipient of the 2021 Shakti P. Duggal Award presented by the International Union of Pure and Applied Physics (IUPAP).

profile photo of Ke Fang
Ke Fang

The Duggal Award was established after cosmic-ray physicist Shakti Duggal’s untimely death in 1982. In honor of Shakti’s long association with cosmic ray physics and his many contributions to the field during his career, his namesake award is given biennially “to recognize an outstanding young scientist for contributions in any branch of cosmic ray physics.” The first Shakti P. Duggal Award was presented at the 19th International Cosmic Ray Conference at La Jolla in 1985. Previous Duggal Award winners have all achieved recognition and prominence in their careers.

Award winners receive a monetary award and, since 1991, an invitation to visit the Bartol Research Institute of the University of Delaware, where Shakti Duggal worked, to present a colloquium and discuss their work.

Fang’s research focuses on understanding the universe through its energetic messengers, including ultra-high-energy cosmic rays, gamma rays, and high-energy neutrinos. She runs numerical simulations to study theories of astroparticle sources and analyzes data from HAWC, Fermi-LAT, and IceCube. She joined WIPAC and the UW–Madison Physics Department as an assistant professor on January 1, 2021. You can learn more about Fang and her research in this Q&A.

“I am very grateful for this special honor,” said Fang. “As a young researcher, I have received enormous support from my mentors and collaborators, to whom the award truly belongs. I look forward to continuing working on and contributing to cosmic ray physics as a member of the Duggal family.”


Physics projects funded in first round of UW’s Research Forward initiative

In its inaugural round of funding, the Office of the Vice Chancellor for Research and Graduate Education’s (OVCRGE) Research Forward initiative selected 11 projects, including two with physics department faculty involvement.

OVCRGE hosts Research Forward to stimulate and support highly innovative and groundbreaking research at the University of Wisconsin–Madison. The initiative is supported by the Wisconsin Alumni Research Foundation (WARF) and will provide funding for 1–2 years, depending on the needs and scope of the project.

The two projects from the department are:

Research Forward seeks to support collaborative, multidisciplinary, multi-investigator research projects that are high-risk, high-impact, and transformative. It seeks to fund research projects that have the potential to fundamentally transform a field of study as well as projects that require significant development prior to the submission of applications for external funding. Collaborative research proposals are welcome from within any of the four divisions (Arts & Humanities, Biological Sciences, Physical Sciences, Social Sciences), as are cross-divisional collaborations.

Several physics majors awarded Hilldale Fellowships

Six UW–Madison undergraduate physics or AMEP majors have been named 2021 Hilldale Fellows, in addition to one computer science major who is conducting their research in the Physics Department.

The Hilldale Undergraduate/Faculty Research Fellowship provides research training and support to undergraduates at UW–Madison. Students have the opportunity to undertake their own research project in collaboration with UW–Madison faculty or research/instructional academic staff. Approximately 97 – 100 Hilldale awards are available each year.

Three students are conducting research in the Department of Physics, including:

  • Mathematics and Physics major Gage Siebert, in Prof. Peter Timbie’s group
  • Physics major Haley Stueber, in Prof. Dan McCammon’s group
  • Computer Sciences major Nikhilesh Venkatasubramanian, in Prof. Tulika Bose’s group

The physics or AMEP majors who have been named Hilldale Fellows and are conducting research outside the department are:

  • Mathematics and Physics major Sam Christianson, with Saverio Spagnolie (Mathematics)
  • Astronomy – Physics, Biochemistry, Chemistry, Mathematics, Molecular & Cell Biology, Neurobiology, Physics, Psychology, and Zoology major Renxi Li, with Catherine Gallagher (Neurology)
  • AMEP major Shenwei Yin, with Joseph Andrews (Mechanical Engineering)
  • Computer Sciences and Physics major Heqiao (Wonder) Zhu, with Kevin Eliceiri (LOCI)