The Department of Physics at the University of Illinois at Urbana-Champaign is known for its collegial style of research—the “Urbana style”—that often involves collaborations across research areas and among theoretical and experimental physicists.
Spectrum - FALL 2024
The Department of Physics at the University of Illinois Urbana-Champaign is known for its long history of collaborative research—the “Urbana style of physics”—that frequently reaches across research areas and involves close coordination between theoretical and experimental physicists. Here is an inside glimpse of what some of our physicists are working on.
KARIN DAHMEN
Theoretical Condensed Matter Physics
JOAQUIN VIEIRA
Observational Cosmology
SMITHA VISHVESHWARA
Theoretical Condensed Matter Physics
HAMIDEH TALAFIAN
Physics Education Research
KARIN DAHMEN
My research group maintains wide-ranging interests in non-equilibrium dynamical systems, including pattern formation, memory in materials, and avalanches in homogeneous and in homogeneous systems having quenched disorder. We are especially interested in recent experiments that show intriguing far-from-equilibrium phenomena.
In physical systems consisting of a large number of atoms or molecules, statistical fluctuations often become small and consequently the signals we perceive are mostly averages over the complex microscopic behavior of the system. However, large classes of systems show fluctuations also on macroscopic scales. We extract information from the statistics of the fluctuations to predict aspects of the systems’ future behavior.
For example, many systems respond to small forcing with sudden pops, snaps, or crackles, which often span many orders of magnitude in size. Examples range from the atomic to the tectonic (see figure). They include daily experiences such as the crackling noise of milk invading Rice Crispies and devastating events, such as earthquakes, landslides, power-grid blackouts, and stock-market crashes. At the scale of systems studied in laboratories, they include slips in crystals, glasses, and densely packed granular materials (such as powders, sand, or grain), magnetization avalanches in magnetic materials, resistivity fluctuations in superconductors, decision-making processes, and neuron-firing avalanches in the brain. On astronomical scales, they may include solar flares and the dimming events of Tabby’s star and other stellar objects.
Our group aims to explain the complex response of these systems to slow forcing, to predict their future behavior, and to discover fundamental connections between different scales and systems. This knowledge is crucial for nondestructive testing and for transferring results from one system to another and from one scale to another (e.g., from lab scales to earthquakes). To achieve these goals, we employ tools from condensed matter physics, statistical physics, computational physics, biophysics, geophysics, astrophysics, and mathematical physics, especially the theory of phase transitions and the renormalization group. We are most grateful to our experimental collaborators, who generously share their data with us to see if our models’ predictions match reality.
Research in the Dahmen group is supported by the U.S. Department of Energy and Sandia National Laboratories’ Directed Research and Development program, Project No. 233080; and by the National Science Foundation under Grant Nos. 2123781 and 2014027. Additional support comes from the University of Illinois Campus Research Board. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the funding agencies.
JOAQUIN VIEIRA
My research aims to understand the physical origins of our universe. To this end, I develop instrumentation and conduct observations to study how the early universe and the first galaxies formed and evolved over cosmic time.
Early in my career, as a graduate student, I helped build the South Pole Telescope to study the cosmic microwave background (CMB). In the course of our work, we discovered a population of high-redshift and strong gravitationally lensed dusty starforming galaxies. That’s a mouthful. More simply stated, there are galaxies in the universe’s early history that formed stars at a prodigious rate but were completely enshrouded in dust and thus invisible at optical wavelengths of light. Averaged over the entire history of the universe, dust absorbs about half the radiation energy ever produced by stars and then reradiates in the infrared. Studying these galaxies in the infrared lets us see the hidden half of galaxy formation and evolution over cosmic time. In a happy coincidence, some of these galaxies perfectly align with a foreground galaxy, which magnifies them by gravitational lensing. First predicted by Einstein’s general theory of relativity, gravitational lensing is a powerful tool in cosmology, serving to magnify the light from otherwise faint galaxies. When combined with the world’s most powerful telescopes, gravitational lensing allows us to study these galaxies in unprecedented detail.
My group has been using the Large Atacama Millimeter/Submillimeter Array (ALMA) and the James Webb Space Telescope (JWST) to do just that. We conducted the first spectroscopic redshift survey with ALMA and detected dusty gravitationally lensed galaxies out to a redshift of z=6.9, where z represents the fractional change in wavelength due to the expansion of the universe. The galaxies we observed date to when our universe was less than a billion years old—the universe is now 13.8 billion years old. We have also studied water and lately even rare isotopes of carbon and oxygen in these galaxies, so we are literally doing chemistry in the early universe. More recently, my group was among the first to observe with JWST, and we have been studying dust and the stellar populations in these distant galaxies.
I am the principal investigator of a NASA experiment called the Terahertz Intensity Mapper (TIM), designed to make 3D maps of the universe. TIM comprises a novel camera attached to a 2-meter-diameter telescope, which we will fly by helium balloon above Antarctica to map the distribution of ionized carbon in the redshift range of z=0.5–1.5 (that’s when the universe was from 4 to 8 billion years old). We plan to study the history of cosmic star formation with this instrument, which also serves as a prototype for a larger future NASA space mission.
On even longer time scales, I am involved in the next-generation CMB experiment, called CMB Stage-IV (CMB-S4), which aims to constrain the epoch of inflation in the first instants of the universe. Along the way, we will do a lot of other exciting science, including studying how the millimeter sky changes on short time scales—from minutes to months. In this research, we’ll tend to look at nearby objects, such as stars in our own galaxy. This is fun for me. It’s a rare and exciting opportunity to think about objects and processes in the nearby universe.
Research in the Vieira group related to the Terahertz Intensity Mapper experiment is supported by NASA under Grant No. 80NSSC24K1881. Additional funding for research related to the South Pole Telescope comes from the National Science Foundation under Grant Nos. 1852617 and 2332483. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the funding agencies.
SMITHA VISHVESHWARA
Suppose you knew how an individual behaved, be it an electron, a grain of sand, or a child on a soccer field. Now ask yourself how a collection of such individuals who are strongly interacting with each other would act as a whole. It’s a challenging question. Collective behavior—be it the coordinated dance of electric current in metals, dunes changing shape in a desert, or the creation of a stadium wave—may bear no resemblance to the behavior of the individual. As condensed matter physicists, it is the collective behavior that we study (though rarely in the mind-boggling human realm), and a good fraction of us add the mysteries of quantum physics to the mix. As a pen-and-paper theorist, I equally love letting imagination run unfettered by reality and working with experimental colleagues who show us the magic of quantum matter that can actually be realized.
The principles of condensed matter physics have enabled my group and collaborators to explore a range of phenomena from the atomic to the cosmic scales, both in and out of equilibrium. Quantum-ordered states of matter traverse these scales. In some cases, the order is local, as in magnets where large collections of spins primarily point in the same direction, or in superconductors and superfluids. In other cases, the order is hidden, as in quantum Hall systems, hailed for their ability to measure a combination of fundamental constants of Nature, or other topological states that have recently come into the limelight. Of the various features we study in these states, one of my favorites involves fractionalization. In strongly correlated systems—quantum Hall fluids or nanotubes, for instance—collective behavior gives rise to quasiparticles that are composed of the underlying soup of particles but appear nothing like them. An orthogonality catastrophe, as it is dramatically referred to, the quasiparticles could have a fraction of an electron’s charge or quantum statistics different from those of the fermions and bosons composing the universe. Such quasiparticles, known as anyons, could bear good promise for topological quantum computation. After decades of work, experiments have recently detected these anyons, leading our community to explore these quasiparticles with renewed verve.
In another line of study, we are investigating superfluids, specifically Bose-Einstein condensates in shell-shaped geometries. In the past decades, experimentalists have mastered creating the coldest spaces in the universe right here on Earth, to host condensates. Now they are doing so aboard the International Space Station. Among these experimentalists, our own experimental collaborators have succeeded in creating these ultracold shell condensates away from gravity’s grip. In addition to the thrill of these studies, I have had the privilege of working with my parents, both scientists. With my mother, we have applied principles of percolation (yes, also common to coffee-making) to understand protein structure, lately focusing on the spike protein associated with COVID-19. In my correspondence with my late father, a general relativist, he inspired me to draw parallels between black-hole-based gravitational waves and condensed matter physics. A popular-science book we began on quantum physics and relativity, written as letters between father and daughter, is slated to be published in January 2025.
As another major chapter, I am now on a euphoric journey, collaboratively melding my two passions—physics and the arts. Works that we scientists and artists have created include the theater piece Quantum Voyages, the circus performance Cosmic Tumbles, Quantum Leaps, and the short film Solaria. In a project-based interdisciplinary course that I developed and that is now part of our curriculum, Where the Arts Meets Physics, students unleash the imagination and give rise to marvelous creations. Our communities have celebrated physics-art-culture confluences by organizing art-science festivals and outreach events, including special programming with the American Physical Society; big festivities are in store for the 2025 International Year of the Quantum. My collaborators and I have now come together on campus as CASCaDe, the Collective for Art-Science, Creativity, and Discovery, etc.
Research in the Smitha Vishveshwara group is supported by NASA under Jet Propulsion Laboratory Research Support Agreement No. 1699891; and by the National Science Foundation under Grant No. DMR-2004825. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the funding agencies.
HAMIDEH TALAFIAN
I am a postdoctoral research associate who earned my Ph.D. in 2020 in educational leadership and learning technologies with a concentration in STEM education. Currently, I work with the physics education research group on multiple projects aimed at enhancing the quality of physics instruction in both high schools and higher education. My research integrates STEM education, learning sciences, educational psychology, and educational technologies. Over the past decade, I have designed and evaluated K–12 physics and chemistry curricula, facilitated professional development for teachers, developed informal learning programs for minoritized students, and leveraged digital technologies to enhance science instruction.
One of my significant projects involves working with the Illinois Physics and Secondary Science (IPaSS) program, a partnership between Illinois Physics and high school teachers across the state. The IPaSS community supports teachers in diverse geographic, ethnic, and cultural settings by facilitating the design and implementation of high-quality, university-aligned instructional materials. My research examines how professional development structures and mentoring support novice and out-of-field teachers in implementing reform-based instruction. Our findings highlight the effectiveness of a responsive professional development model, where teachers actively participate in collaborative problem-solving sessions and co-design workshops. This approach shifts teachers from passive knowledge recipients to socially active learners, fostering inquiry-oriented teaching identities and ultimately empowering students with greater agency in experimental design.
Addressing the nationwide shortage of physics teachers is another critical focus of my work. Through the Noyce Teacher Scholarship program, I investigate factors that attract or deter undergraduates from pursuing careers in the physics teaching profession. Despite being one of the world’s leading physics departments, we currently produce very few physics teachers—a trend mirrored across the country. The shortage leads to understaffing, assigning physics courses to teachers without appropriate backgrounds, or even eliminating physics from curricula, particularly at smaller schools. In my research, I design and implement robust support structures within the physics department to create clear and sustainable pathways for students interested in high school teaching careers. These structures include fostering peer-support communities, organizing regular monthly meetings, and inviting guest speakers to share real-world insights and experiences. Additionally, I introduce and promote retention initiatives, such as the IPaSS program within our department, which provides ongoing mentorship and resources to guide and support in-service teachers throughout their journey. These efforts aim to build a comprehensive and research-driven framework that empowers future educators and ensures their long-term success in the field.
Another key focus of my work is enhancing the quality of introductory physics courses for both physics majors and non-majors. These courses serve as critical gateway experiences for engineering students, making their improvement essential to supporting student success and retention. We are enhancing the occurrence and quality of students’ interactions in these courses by introducing whiteboards as shared displays and improving TA training to foster better group interactions during discussions. While reform-based practices have made strides, there is still significant room for improvement in the implementation of collaborative problem-solving exercises. My research focuses on developing students’ collaborative, cognitive, and metacognitive skills and equipping TAs to support these skills. This approach better prepares students for collaborative learning and problem-solving, both in academic settings and future professional environments.
The ultimate goal of my research is to foster a more robust and equitable physics education landscape. My research bridges theory and practice, contributing to sustainable solutions that advance science teaching and learning in diverse educational settings.
Hamideh Talafian’s research is supported by the National Science Foundation under Grant Nos. 2010188 and 2345132. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the funding agency.