Each week during the semester, the Department of Physics invites faculty, students and the local community to hear prominent scientists discuss intriguing physics research. Unless otherwise noted, colloquia are held Tuesdays in room 1410 of the John S. Toll Physics Building at 4:00 p.m. (preceded by light refreshments at 3:30 p.m.)
For further information, please contact the Physics Department at 301-405-5946 or email This email address is being protected from spambots. You need JavaScript enabled to view it..
September 5 | Smitha Vishveshwara, University of IllinoisHosted by Jay Sau and Johnpierre Paglione
Quantum Escapades: From nanoconstrictions to black holesTime and again, one encounters marvelous unifying physics that links phenomena from the most miniscule to astronomical scales. Universal phase transitions in magnets, superconductors, and the cosmos; simple harmonic motion from neutrinos to fluids to galaxies; defect and structure formation in the early Universe and in liquid Helium---to name just a few. Here, we explore how the inverted harmonic oscillator, the lesser known sister of the simple harmonic oscillator, offers fertile grounds for the same beautiful dynamics across scales and tantalizing ‘quantum escapades’. In its presence, deep parallels become manifest in quantum Hall systems, quantum optics, and curved spacetime. We journey through these parallels, linking phenomena as disparate as tunneling across point contacts, squeezing, Hawking-Unruh radiation, and black hole ringdown to offer fresh cross-disciplinary perspectives and new predictions. |
September 12 | Abhay Deshpande, Stony Brook University |
September 19 | Jason Hogan, Stanford UniversityHosted by Steve Rolston
Long baseline clock atom interferometry for gravitational wave and dark matter detectionAtom interferometry and atomic clocks continue to make impressive gains in sensitivity and time precision. I will discuss the potential for using atomic sensors for gravitational wave detection and searches for dark matter. Interest in this has driven the growth of the emerging field of long-baseline atomic sensing, which aims to scale up “tabletop” experiments to the kilometer-scale and beyond. Key to this is the development of a new type of “clock” atom interferometry based on narrow-line optical transitions that combines inertial sensitivity with features from the best atomic clocks. This technique is central to the MAGIS-100 experiment, a 100-meter-tall atomic sensor now under construction at Fermilab that will probe for ultra-light dark matter and will serve as a prototype for a future gravitational wave detector targeting the unexplored “mid-band” frequency range. Reaching the sensitivity needed for these ambitious goals also requires substantial advances in atom optics in order to increase the space-time area of the interferometer. I will describe atom optics that use Floquet modulation to reach pulse fidelities exceeding 99.4%, allowing for a record-setting momentum separation between the interferometer arms of over 400 ћk. |
September 26 | Maissam Barkeshli, University of Maryland
Coloring Hofstadter's Butterfly: New Topological Invariants of Crystalline Quantum MatterThe discovery of quantized Hall conductance in the early 1980s showed how quantum phases of matter can be distinguished by topological invariants. This kicked off a decades-long quest to understand subtle distinguishing topological aspects of quantum matter. In this talk, I will describe a new set of topological invariants that arise in quantum systems with crystalline symmetry. Analogous to the quantized Hall conductance, these new invariants dictate quantized responses of the system to crystal defects. Our understanding of how to extract these invariants from quantum systems has provided the first new ways to color Hofstadter's famous fractal butterfly in over 40 years. |
October 3 | R.I. Sujith, Indian Institute of Technology, Madras |
October 10Shih-I Pai | Charles Clark, National Institute of Standards and TechnologyHosted by Konstantina TrivisaGeneration, Detection and Application of Twisted Waves of Light and NeutronsIt was about 50 years ago today, when "Dislocations in wave trains" came into play. Twenty years on, "Dislocations" became a nineties hit following the ingenious experiments of Soskin et al., that showed the promise of applications of twisted or structured light with non-vanishing orbital angular momentum about its propagation axis. Modern use cases for such modalities include increased communication bandwidth for 6G applications. Quantum particle beams can also be shaped by analogue tools of optics. I shall present recent results for neutrons, made possible by microfabricated synthetic holograms containing millions of forked dislocation gratings of the type envisaged by Soskin, et al. |
October 17Paint Branch | John C. Mather, NASA |
October 24Richard E. Prange Prize Lecture | Pablo Jarillo-Hererro, MIT |
October 31 | Eun-Ah Kim, Cornell University |
November 7 | Stephen Taylor, Vanderbilt University |
Friday,November 10 | Kip Thorne, California Institute of Technology4:15 p.m. in 1412 Toll. Part of a memorial weekend for Charles W. Misner.Our Romance with the Warped Side of the UniverseIn the 1950s and early 1960s, when Charlie Misner and I embarked on our careers as physicists, there were hints that our Universe might have a Warped Side: objects and phenomena such as black holes that are made from warped space and time instead of matter. Throughout our long careers, we and our contemporaries have struggled to convert those hints into clear understanding. We have explored the Warped Side through theory (using mathematics and computer simulations to probe what the laws of physics predict) and through astronomical observations (primarily with gravitational waves). In this lecture I will recount the history of those explorations and will describe what we now know about the Warped Side, and will speculate about the future. |
November 14 | Sankar Das Sarma, University of Maryland
Majorana zero modes and topological quantum computation: What, why, how, whenI will discuss the current status of the search for non-Abelian Majorana zero modes (MZMs) and topological superconductivity in solid state systems, from both experimental and theoretical perspectives. In particular, the highly-developed physics of the search for MZMs in hybrid semiconductor-superconductor systems will be discussed along with the analysis of a recent breakthrough experiment from Microsoft Quantum on high-quality InAs nanowires. |
November 21 | Robert Goldston, Princeton University
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November 28 | TBA
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December 5 | Richard L. Greene, University of Maryland |