Kiyong Kim Elected as a Fellow of Optica

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Category: Department News

Published: Thursday, January 30 2025 05:33

Kiyong Kim has been selected as a 2025 Optica Fellow for his pioneering contributions to the generation and understanding of terahertz radiation from strong laser field interactions with matter.  He is one of 121 members, from 27 countries, selected for their significant contributions to the advancement of optics and photonics through education, research, engineering, business leadership and sKiyong Kimervice.

Kim received his B.S. from Korea University and his Ph.D. from the University of Maryland. His graduate research focused on measuring ultrafast dynamics in the interaction of intense laser pulses with gases, atomic clusters, and plasmas. This work earned him the Marshall N. Rosenbluth Outstanding Doctoral Thesis Award from the American Physical Society.

Following his doctoral studies, Kim moved to Los Alamos National Laboratory as a Director’s Postdoctoral Fellow and while there received a Distinguished Performance Award. After accepting a position as an Assistant Professor at the University of Maryland in 2008, he received a DOE Early Career Research Award and an NSF Faculty Early Career Development Award. Kim also received the departmental Richard A. Ferrell Distinguished Faculty Fellowship in 2014.

From 2021 to 2022, Kim held appointments at Gwangju Institute of Science and Technology (GIST) and the Center for Relativistic Laser Science (CoReLS) at the Korean Institute for Basic Science, leading experiments on petawatt laser-driven electron acceleration, nonlinear Compton scattering of petawatt laser pulses and GeV electrons, and high-power terahertz generation.

With colleagues in physics and the Institute for Research in Electronics & Applied Physics (IREAP), he is co-PI on a $1.61M Major Research Instrumentation (MRI) award from the National Science Foundation (NSF) to upgrade high-power laser systems at UMD.

Finding the Beauty in Physics

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Category: Department News

Published: Wednesday, January 29 2025 01:40

Phoebe Hamilton’s (M.S. ’11, Ph.D. ’13, physics) research career at the University of Maryland could have ended when she earned her Ph.D. Instead, it marked the start of an exciting challenge—for Hamilton and her fellow high-energy physics researchers in UMD’s Department of Physics.
Phoebe Hamilton, Elizabeth Kowalczyk and Othello Gomes check a photodetector.In fall 2012, Distinguished University Professor and Gus T. Zorn Professor Hassan Jawahery eyed a new opportunity after his research group wrapped up with BaBar, a collider experiment in California.

“BaBar had finished collecting new data and we were looking for the next gig for the group,” Hamilton recalled. “Hassan was my Ph.D. advisor and we talked about how exciting it would be to move to the Large Hadron Collider beauty—LHCb—experiment.”

Just two months before Hamilton defended her dissertation, Jawahery’s group learned that they had been formally accepted into the LHCb experiment, which is named after its primary research subject: a particle called the beauty quark, also known as a bottom quark or b quark. By studying bottom quarks produced by proton-proton collisions at the Large Hadron Collider located near Geneva, Switzerland, researchers hope to come closer to understanding why there is so much matter but so little antimatter in the universe.

Excited by the opportunity to discover new physics at the world’s most powerful particle accelerator, Hamilton stayed at UMD. As a postdoctoral researcher from 2012 to 2020 and a faculty specialist from 2020 to 2023, she developed tools that enabled the LHCb to take measurements previously thought “impossible” by some scientists.

Now, as an assistant professor of physics, her contributions continue to level up the LHCb’s abilities, improving its chances of making groundbreaking findings.

“Getting to stay a postdoc as long as I did at Maryland was a real blessing,” Hamilton said. “I wasn’t sure I’d actually have the chance to become an assistant professor, but I'm very happy to get to do it. Maryland is such a home and such a family to me.”

Raising the BaBar

Hamilton’s interest in physics began in high school and she nurtured it with books about string theory by physicist Brian Greene. After graduating, she enrolled at Youngstown State University to pursue computer science, another one of her interests, but switched to physics after realizing that it inspired and challenged her more than any other subject.

“I like knowing how things work,” said Hamilton, who also enjoys learning new musical instruments for similar reasons. “The fact that physics is orderly and follows these predictable rules has always been fascinating to me.”

Hamilton quickly took to particle physics, and after earning her bachelor’s degree in 2007, she decided to pursue particle theory research in UMD’s graduate program. She chose UMD because of its wide range of research possibilities, which allowed her to try out different specializations before committing.

“I thought I knew what I wanted to do, but there was doubt,” she said. “With UMD, I thought to myself, ‘This is where I’m going to be able to thrive no matter what I do.’”

Hamilton soon discovered she enjoyed the experimental side of particle physics much more than theory. So when Associate Professor Doug Roberts put up flyers seeking student researchers for the BaBar experiment, Hamilton jumped at the chance.

BaBar was Hamilton’s introduction to experimental studies of CP violation, which occurs when two conservation laws of particle physics—charge conjugation and parity—are broken. By measuring CP violation at experiments like BaBar, researchers can begin to understand the differences between matter and antimatter.

“I fell in love with it very quickly,” Hamilton said of BaBar. “It was a fantastic machine and a fantastic experiment.”

Hamilton’s research contributed to the first measurement of how Bs mesons, a family of subatomic particles called mesons that contain a bottom quark and a strange antiquark, are produced at different collision energies. Ultimately, the BaBar experiment shed light on how antimatter is produced and set the stage for Hamilton’s participation in an even bigger—but messier—collider.

“The beautiful thing at BaBar was that you would get two hadrons containing bottom quarks and nothing else, so it was very clean and very easy to measure what was going on,” Hamilton said. “Here [at the LHCb], colliding protons is like colliding handfuls of rock salt. You get 100 reconstructed particles in every event and you have to sort through it.”

Achieving the ‘impossible’

For the last 12 years, Hamilton has been working to make those messy collisions a little easier to interpret. UMD’s contribution to the LHCb experiment falls within the realm of lepton flavor universality: a physics principle stating that the only difference between different “flavors,” or types, of leptons—including electrons, muons and tau leptons—is their mass. 

The LHCb is a good fit for this type of research because it analyzes a large number of particles containing b quarks, which transform, or decay, into leptons. In the beginning, though, some scientists thought that lepton flavor universality couldn’t be done at the LHCb because either one or three neutrinos escape undetected during collisions, making it difficult to determine all of the energies and momenta needed to distinguish muons from tau leptons. 

“Because of the messy nature of these proton-proton collisions, the consensus was that this was too hard for LHCb to do,” Hamilton said. “But Jawahery and I worked together on a technique to make some wild approximations and figure out a way to do it anyway.”

And they did figure out a way. Developed from 2013 to 2015 in collaboration with LHCb researcher Greg Ciezarek, their method of analyzing decays led to measurements of lepton flavor universality between muons and tau leptons that were previously thought impossible. 

“It was interesting to go from ‘This is probably another dead-end’ to ‘Oh, this might actually be worth something’ to ‘This is actually the star of the experiment right now,’” Hamilton said. “This is still an active area of research for us. We extended and superseded the 2015 measurement in 2023 and are working on the next generation of this in the data from the second run of the LHC.”

Cracking the K-pi puzzle

Over the years, Hamilton has also played a key role in making the LHCb’s equipment more durable and better at discerning different particles. She helped develop electronics for the Upstream Tracker sub-detector for the experiment’s first upgrade from 2022 to 2023 and is now testing new photodetectors in her lab. These new detectors would measure the light produced in upgraded modules for the LHCb’s calorimeter, which stops particles as they pass through and enables researchers to measure the energy deposited. 

This planned upgrade to the calorimeter aims to make energy measurements more precise, which can ultimately help researchers determine which particles were produced in a collision event.

“One of the big motivations for upgrading the calorimeter is making some of the granularity smaller so that you can tell different particles apart,” Hamilton explained. “Along with the ability to precisely measure the time different particles arrive, it should in principle be able to cope with five times the collision rate.”

Whether Hamilton is toiling in the lab or analyzing data from the LHCb, she continues to find inspiration in physics’ most puzzling questions. She recently submitted a research proposal to dive deeper into matter-antimatter asymmetries and continues to work on developing new and improved techniques for her research. 

From 2014 to 2015, she and her colleagues at UMD developed a way to study b-hadron decays with only one reconstructed trajectory, meaning that certain key information is missing. She believes this technique can now be applied to a persistent challenge in physics called the K-pi puzzle.

“The K-pi puzzle is the possibility that the Standard Model fails to explain the pattern of matter-antimatter asymmetry in b-hadron decays to two pseudo-stable mesons, pions or kaons—or one of each. The Standard Model predicts specific patterns to their CP asymmetries, which we can use to check the Standard Model’s validity, but theorists need measurements of them all,” Hamilton explained. “Some of these involve two trajectories to reconstruct and identify the b-hadron but many do not, and these tend to be the less understood ones.”

Going forward, Hamilton hopes to make more “impossible measurements”—and perhaps challenge or reshape the Standard Model of physics in the process.

“We have an opportunity to contribute to understanding this puzzle in some of the areas that are fuzziest right now,” Hamilton said, “and I think there's exciting things to be tried there.”

Written by Emily Nunez

Connecting the Quantum Dots

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Category: Department News

Published: Wednesday, January 29 2025 01:40

Physics Ph.D. student Anantha Rao tests ways to build bigger and better quantum computers.

Anantha Rao grew up in Bengaluru, a city known as India’s tech hub due to its bustling startup culture and many international IT corporations. While many of Rao’s peers pursued engineering and related subjects, Rao’s love of science and knack for solving mathematical problems nudged him in a different direction.

“Everyone around me was an engineer or wanted to be one, and that is one thing I did not want to be,” Rao said. “I had this rebellious nature of going against the crowd, but I also wanted to solve fundamental problems in the basic sciences for the love of it—not for immediate applications.”

Rao discovered his calling after winning a high school physics competition. As a prize, he received a book written by Richard Feynman, a theoretical physicist who laid the groundwork for the field of quantum computing more than 40 years ago, and the field’s endless applications captivated Rao.

“Quantum computing has applications in studying how drug molecules bind to receptors or decrypting credit card transactions. You could study models of how the universe was created or see how the first molecule came into the picture,” Rao said. “Using ideas from quantum mechanics and computer science, you can also build better quantum computers, which is the problem that I’m looking at today.”

Now a Ph.D. student in the University of Maryland’s Department of Physics and Joint Center for Quantum Information and Computer Science (QuICS), Rao probes the fundamental physics that could power the next generation of quantum computers. He said he’s grateful for the chance to pursue that challenge in the “Capital of Quantum” at UMD.

“UMD is one of the top schools in the world for quantum information, especially theory,” Rao said. “Ten years ago, if someone told me that I'd be here now, I would feel like it is a dream.”

Tackling malaria with tech

Before moving to the United States, Rao was a full-time physics student and part-time entrepreneur in India. While Rao was enrolled in a combined bachelor’s and master’s program at the Indian Institute of Science Education and Research Pune, he cofounded a startup to develop diagnostic tools for diseases like malaria, a mosquito-borne infection that kills an estimated 608,000 people per year, according to the U.S. Centers for Disease Control and Prevention.

The software he developed, dubbed Deep Learning for Malaria Detection (DeleMa Detect), relied on artificial intelligence (AI) to search patients’ blood smear images for the signs and stages of malaria infection. This technology is packed into a small, portable device, reducing the need for lab tests that can be costly and inaccessible in many parts of the world.

Rao’s startup received a $50,000 grant and won top prize at the International Genetically Engineered Machine (iGEM) 2021 Startup Showcase. Rao has since moved on to other projects but said his early entrepreneurial experience taught him lessons about project leadership and collaboration that he applies to his research every day.

“I learned a lot about AI during my brief stint with entrepreneurship, and that’s something I've been working on lately—using AI to solve problems in physics,” Rao said. “My main motivation now is: What are the toughest problems out there and how can I solve them?Rao at TU Delft.

Since joining UMD’s physics Ph.D. program in 2023, he has been working to identify—and answer—those questions, one at a time.

The making of MAViS

One of Rao’s biggest ongoing projects is a collaboration between UMD, the National Institute of Standards and Technology and Delft University of Technology in the Netherlands. He has been leading the Modular Autonomous Virtualization System for Two-Dimensional Semiconductor Quantum Dot Arrays (MAViS) project, which aims to advance research that could lead to bigger and better quantum dot-based quantum computers.

Central to this concept are quantum dots, tiny semiconductor particles that serve as the building blocks of some quantum computers. These quantum computers operate at temperatures close to absolute zero, or −273.15 degrees Celsius—conditions that prompt the chips to engage in quantum mechanical behavior.

“The chips in your phone and chips in your laptop are made up of semiconductors, and similarly, we have quantum computers made out of semiconductors, except they operate at the coldest temperatures in the universe,” Rao explained. “The problem is you can't control them very well and you have a lot of unwanted interactions coming in.

To control each quantum dot, voltages must be applied to electrodes in their vicinity. Isolating this task can be tricky, though, because quantum dots are spaced just a few nanometers apart.

“What MAViS offers is a way to independently control each quantum dot in a very scalable and efficient way. This is a process called virtualization,” Rao explained. “Most importantly, it’s completely automatic. You press a button and MAViS solves a lot of equations faster than any human.”

By finding ways to offset unwanted interactions, which can introduce errors, researchers can make quantum computers run more efficiently and accurately. MAViS also uses “a little bit of AI” to enable corrections in real-time, Rao said.

Rao and his collaborators have seen encouraging results after testing MAViS on some of the world’s largest quantum dot devices in the Netherlands. MAViS successfully enabled researchers to operate and more efficiently control quantum dots, which in turn helps them control qubits—the fundamental building blocks of quantum computers.

Rao explained that one of the benefits of MAViS is that it works quickly and could free up time for researchers to focus on deeper tasks.

“We were able to do a task in about four hours that would have taken a month or two months of human effort,” Rao said. “Without MAViS, a lot of people with doctorate degrees would have needed to stare at computer screens and analyze complicated images to solve this problem. Now, researchers can automatically ‘virtualize’ their quantum dots and perform interesting experiments.”

Aside from his research with MAViS, Rao said his research on semiconductor qubits has also revealed some unusual physics, including elusive crystals made entirely of electrons.

“Another question in my research is: If you have these semiconductor quantum dots or quantum computers, what is some interesting physics that one could study in one dimension or two dimensions?” Rao said. “We've found evidence that exotic phases of matter—something called Wigner crystals—could be found in these devices.”

Giving back

As Rao dives deeper into quantum physics, he continually seeks ways to share his knowledge. MAViS and many of Rao’s past research projects involve open-source code so that the community at large can benefit.

“Since undergrad, I’ve wanted to give back to the community as I’ve learned things, and one way is through open-source projects and mentoring other students,” said Rao, who also worked as a teaching assistant and served on graduate student committees at UMD. “We hope to eventually make MAViS open source so that people anywhere in the world can build better, scalable quantum-dot quantum computers.”

After Rao graduates, he hopes to find a job that will enable him to keep tackling the big questions in quantum physics, whether that’s in academia or private industry.

“My pursuit is the best research and the best science that I can do today, and I believe that approach will give me the right opportunity in an academic lab or industry lab,” Rao said. “There are a lot of problems to solve in quantum, and I’m working toward solving them one at a time.”

Written by Emily Nunez; published March, 2025

Malcolm Maas Named 2025-26 Churchill Scholar

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Category: Department News

Published: Wednesday, January 29 2025 01:40

University of Maryland senior Malcolm Maas has been awarded a 2025-26 Churchill Scholarship, joining only 15 other science, engineering and mathematics students nationwide in winning the prestigious honor. 

“We could not be prouder of how Malcolm Maas represents the University of Maryland to the world,” said Amitabh Varshney, dean of UMD’s College of Computer, Mathematical, and Natural Sciences. “Malcolm is a phenomenal student researcher who is driven to understand complex world problems like climate change and provide innovative solutions to them.”Malcolm Maas. Photo courtesy of same.

Maas, who plans to graduate in three years with bachelor’s degrees in atmospheric and oceanic science (AOSC) and physics, will receive full funding to pursue a one-year master’s degree at the University of Cambridge’s Churchill College in the United Kingdom. The scholarship covers full tuition, a competitive stipend, travel costs and the chance to apply for a special research grant. 

Maas plans to pursue a Master of Philosophy degree in mathematics.

“I feel incredibly honored to have received this scholarship, and I’m very grateful to everyone who has supported me on my way here,” Maas said. “I’m excited for the opportunity to explore atmospheric dynamics further and to experience Cambridge next year.”

A total of 127 nominations this year came from 82 participating institutions. Ten UMD students have been nominated in the past seven years—and nine of them have been named Churchill Scholars.

“The University of Maryland’s remarkable success in racking up Churchill Scholarships testifies to the excellence of the research opportunities and mentorship our undergraduates receive,” said Francis DuVinage, director of UMD’s National Scholarships Office. “Malcolm Maas’ record of accomplishment as a third-year senior puts him in a class by himself.”

Since 2022, Maas has been working with AOSC Associate Professor Jonathan Poterjoy on fundamental challenges associated with environmental prediction and validation of atmospheric modeling systems. Specifically, he is quantifying the degree to which commonly used data assimilation methods shift models away from physically plausible solutions due to commonly adopted but incorrect assumptions. Maas presented their work in January 2025 at the American Meteorological Society Annual Meeting.

“Malcolm initiated our research collaboration on his own and I fully expect him to draft a first-author paper that we submit for publication this year,” Poterjoy said. “I feel that Malcolm can succeed in virtually any field, and I am pleased to see that he chose a research career in atmospheric science where his talents can have broad human impact.” 

Maas’ research interests and experiences extend beyond his work with Poterjoy and currently range from weather time scales to climate time scales. 

In summer 2024, Maas interned at the University of Chicago with Geophysical Sciences Professor Tiffany Shaw, where he assessed extreme heat and atmospheric circulation trends associated with Arctic sea ice loss in climate models and observational datasets. He presented this work at the American Geophysical Union’s Annual Meeting in 2024.

In summer 2023, Maas participated in the undergraduate summer intern program at the Lamont-Doherty Earth Observatory and worked on a project with Kostas Tsigaridis, a research scientist at Columbia University and the NASA Goddard Institute for Space Studies. Maas used a large dataset of Earth system model simulations to explore the effects of volcanoes on climate and atmospheric sulfur. He used machine learning to develop a tool that estimates where unidentified historical eruptions happened based on ice core data. Maas presented this work at the European Geosciences Union’s General Assembly in 2024 in Austria.

When Maas arrived at UMD in 2022, he joined a group of AOSC students installing and managing a micronet—a small-scale network of weather sensors—across the university’s campus. Five weather stations now provide minute-by-minute updates on the temperature, wind speed, pressure, dew point and rain rate on campus. Maas helped create the data collection system and user-friendly graphs to visualize the data, which are displayed on the UMD Weather website.

When the university and the Maryland Department of Emergency Management installed their first weather tower as part of the Maryland Mesonet in 2023, they asked Maas to quickly adapt his micronet visualization tools to work with the mesonet data. The 23 towers operational around the state—with more than 70 planned—help to advance localized weather prediction and ensure the safety of Maryland's residents and visitors.

For his Gemstone honors research project, Maas and 10 teammates have been working with UMD Mechanical Engineering Professor Johan Larsson to optimize the shape of marine propellers.

In high school, Maas helped build the first global tornado climatology database. He gathered and processed historical data for over 100,000 tornadoes that occurred around the world. The project’s website raked in 160,000 page views during its first year, and the work was published in the Bulletin of the American Meteorological Society in 2024.

Outside of class, Maas plays the pipe organ, represents the Ellicott Community on the Student Government Association, tutors with the Society of Physics Students and is a member of the Ballooning Club. He received a Barry M. Goldwater Scholarship, National Merit Scholarship, President’s Scholarship and the Department of Physics’ Angelo Bardasis Scholarship.

After his time at the University of Cambridge, Maas plans to pursue a Ph.D. in atmospheric science.