Calendar - Department of Physics and Astronomy

Sep 8, 2026: Physics/Astronomy Colloquium: Hector Okada Da Silva at Lewis Hall

Tue, 08 Sep 2026 16:00:00 -0500

Speaker: Hector Okada Da Silva, University of Illinois Urbana-Champaign

Title: Illuminating the strong-field regime of gravity

Abstract: Neutron stars are some of the most extreme objects in Nature. Their typical masses (about 1.4 times that of the Sun) combined with their small radii (about 12 km) result in densities exceeding the nuclear saturation density, above which exotic states of matter can form. Moreover, neutron stars are the strongest gravitational field sources known, second only to black holes. These properties make neutron stars outstanding laboratories to study matter and gravity in situations out of reach of terrestrial and Solar System experiments. The observation of the x-ray pulse profile emitted by hotspots on the surface of neutron stars, as observed by the Neutron Star Interior Composition Explorer (NICER), offers a unique tool to measure the properties of these objects. The x-ray emission takes place near the star’s surface, where the gravitational field is strong, making these observations an incisive probe into the spacetime curvature generated by these stars. In this colloquium, I will discuss how general relativity plays a key role in the accurate modeling of pulse profiles and the prospects for testing Einstein's theory - and some of its contenders - using these observations.

Refreshments at 3:45pm in Lewis 104

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Sep 15, 2026: Physics/Astronomy Colloquium: Sriparna Bhattacharya at Lewis Hall

Tue, 15 Sep 2026 16:00:00 -0500

Speaker: Sriparna Bhattacharya, Clemson University

Title: Using light to open doors for next-generation thermoelectrics and chemical imaging techniques

Abstract: My talk will focus on using light to decode fundamental mechanisms in materials research. As two broad examples, I’ll discuss how Raman spectroscopy has helped identify phonons that drive anharmonicity in binary chalcogenides (e.g., SnSe and GeTe), leading to their intrinsically low lattice thermal conductivity and a high figure-of-merit for converting waste heat into electricity. Experimental evidence will be presented demonstrating that light is more effective than transport measurements in advancing phonon-engineering approaches to improve thermoelectric material performance. My other example includes the design of a new luminescence-based chemical imaging technique that shows promise for non-invasive detection of implant infection. The luminescence in our imaging technique is activated by ultrasound, enabling much-needed deep-tissue, non-invasive, early detection of implant-associated infections.

This work on binary chalcogenides was performed in collaboration with Prof. Y-Y. Chen’s group in Academia Sinica, Taiwan, Prof. A.M. Rao’s group at Clemson University, and Dr. Rahul Rao, Air Force Research Laboratory, WPAFB, Dayton, OH, 45433 USA. The new luminescence-based chemical imaging technique was jointly developed in collaboration with Profs. J. N. Anker’s and A. M. Rao’s research teams at Clemson University.

Biography: Sriparna Bhattacharya is a Research Associate Professor at the Department of Physics and Astronomy, the Lab Manager at the Clemson Nanomaterials Institute, and a Faculty Scholar at the School of Health Research at Clemson University. Her broad research interests include waste-heat harvesting using electron- and hole-based, as well as ion-based, thermoelectrics. Recently, she collaborated with Prof. H. J. Goldsmid, aka the ‘Father of Thermoelectrics,’ (School of Physics, University of New South Wales, Sydney, Australia), to develop a new evaluation method for thermoelectric materials. This study was featured as the Editor’s Pick by the Editorial Board of the Journal of Applied Physics. She is also passionate about improving lives in the State of SC and beyond. She is developing chemical imaging methods for early detection of infection in biomedical applications.

Refreshments at 3:45pm in Lewis 104

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Sep 22, 2026: Physics/Astronomy Colloquium: Yang Zhang at Lewis Hall

Tue, 22 Sep 2026 16:00:00 -0500

Speaker: Yang Zhang, University of Tennessee, Knoxville

Title: Electron Pairing and Fractionalization in the Age of AI and Quantum Computing

Abstract:

Electrons in solids can do two remarkable things: they can pair up and flow without resistance, and they can collectively behave as fractionally charged particle. Predicting either remains a major challenge because the physics spans enormous spatial scales and exponentially large quantum state spaces. In this talk, I will show how my group uses artificial intelligence to tackle these challenges. Machine-learned Hamiltonians reproduce moiré electronic structures with meV accuracy for systems of up to millions of atoms, enabling studies of superconductivity from weak to strong coupling in twisted semiconductors. For the second, we turn to quantum processors. which can directly represent and manipulate highly entangled states. Constant-depth circuits prepare 18 fractional quantum Hall states up to 156 qubits. Remarkably, some of the most exotic states are also the easiest to prepare. Together, these efforts show how AI can extend quantum-materials modeling to realistic scales, while quantum processors open access to states beyond classical reach.

Bio: Yang Zhang is an Assistant Professor of Physics at the University of Tennessee, Knoxville. He earned his bachelor’s degree in physics and mathematics from Tsinghua University in 2015, followed by a Ph.D. in Physics from the Max Planck Dresden in 2019, then he worked as a postdoc at MIT until 2022. Dr. Zhang has received several awards, including two overall Winner Awards in the World Supercomputing Contest, SFB Best Doctoral Thesis Award, the Tschirnhaus Medal from the Leibniz Association, the Otto-Hahn Medal of the Max Planck Society, International Union of Pure and Applied Physics (IUPAP) Early Career Scientist Prize in Computational Physics, and Haslam family professor from UT Knoxville. Dr. Zhang's research focuses on topological and correlated quantum states, quantum transport, and quantum computation, using a combined first-principle and many-body simulation approach.

Refreshments at 3:45pm in Lewis 104

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