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PHYSICS COLLOQUIUM SCHEDULE

Spring 2021

The Colloquia are via Zoom on Thursdays at 4:05 PM

Contact: D. Tanner uftanner@ufl.edu)
Department of Physics Colloquium Committee:
Tanner (chair), Mitselmakher, Ramond, Wang, B. Xue, X.X. Zhang.

January 14
	Speaker
	Title
	Abstract
	Host

January 21
	Speaker	John Klauder, University of Florida
	Title	From Harmonic Oscillators to Quantum Gravity
	Abstract	Canonical quantization (CQ) has been successful in solving many problems, and is a tool used for nearly all cases. But CQ has not worked well for some problems that have resisted any acceptable solution. Happily, the harmonic oscillator, with -∞ < p,q < ∞, is well solved. However, for the half-harmonic oscillator, where -∞ < p < ∞ while 0 < q < ∞ CQ fails significantly. Likewise, quantum gravity has failed with CQ as well. A new quantization process called affine quantization (AQ) will be introduced. AQ leads to acceptable solutions for the half-harmonic oscillator and shows considerable success for quantum gravity. This lecture will demonstrate the solution of the half-harmonic oscillator and leads to a meaningful Schrödinger equation for quantum gravity, which is in position to seek appropriate solutions from complex differential equations.
	Host	Sergei Shabanov

January 28
	Speaker	Pierre Sikivie, UF Physics
	Title	Encounters with the Axion
	Abstract	The notion of Peccei-Quinn symmetry with its concomitant axion has been astonishingly fertile, with surprising connections to most subfields of physics. A personal account is given of events, insights and experiments that contributed to its history so far.
	Host	David Tanner

February 4 (jointly organized with MAE)
	Speaker	David Wiese, NASA Jet Propulsion Laboratory, CIT
	Title	Chasing Water: Tracking changes in Earth's water cycle from space
	Abstract	The Gravity Recovery and Climate Experiment (GRACE), launched in 2002, provided pioneering observations of changes in surface mass on our planet by measuring variations in the gravitational potential of Earth. These observations quantified, for the first time, the mass balance of the ice sheets, the mass component of sea level change, glacier mass change worldwide, and identified regions of rapid groundwater depletion, raising concern for future regional water security. The GRACE mission was decommissioned in 2017 due to battery failure; however, GRACE Follow-On (GRACE-FO) launched in 2018 and is now successfully continuing observations of Earth system mass change. Further, the 2017 U.S. Earth Science and Applications from Space Decadal Survey listed Mass Change as a Designated Observable, paving the way for a future mission after GRACE-FO. In this talk, I will provide an overview of the measurement system characteristics and scientific highlights from the GRACE and GRACE-FO missions. I will also discuss current efforts underway both in the United States and Europe to develop observing systems that will continue the timeseries of surface mass change into the future beyond the lifetime of GRACE-FO, and have the potential to advance knowledge of surface mass change through improved spatio-temporal sampling characteristics and instrumentation.
	Host	Pep Sanjuan (Physics), John Conklin (MAE)

February 11
	Speaker	Julie Comerford, University of Colorado
	Title	Cosmic Collisions: Galaxies, Black Holes, and Gravitational Waves
	Abstract	Galaxy mergers play an important role in the evolution of the universe, since mergers trigger star formation, build up the mass of supermassive black holes, and drive supermassive black hole mergers that are strong sources of gravitational waves. However, accurate identification of galaxy mergers has been a persistent observational challenge that limits progress in these areas. Here, I will present new approaches to galaxy merger identification, including approaches that use stellar kinematics instead of imaging alone, and approaches that are trained on state-of-the-art cosmological simulations of galaxies. I will summarize the results of our study of galaxy mergers imaged by the Hubble Space Telescope, where we measure the impact of mergers on star formation and supermassive black hole growth. With our new measurements of the galaxy merger rate, we can predict the amplitude of the gravitational wave background produced by merging supermassive black holes. Pulsar timing arrays expect to make the exciting detection of this gravitational wave background within the coming few years.
	Host	Laura Blecha

February 18
	Speaker	Christopher Jarzynski (University of Maryland)
	Title	Scaling down the laws of thermodynamics
	Abstract	Thermodynamics provides a robust conceptual framework and set of laws that govern the exchange of energy and matter. Although these laws were originally articulated for macroscopic objects, nanoscale systems also exhibit "thermodynamic-like" behavior - for instance, biomolecular motors convert chemical fuel into mechanical work, and single molecules exhibit hysteresis when manipulated using optical tweezers. To what extent can the laws of thermodynamics be scaled down to apply to individual microscopic systems, and what new features emerge at the nanoscale? I will describe some of the challenges and recent progress - both theoretical and experimental – associated with addressing these questions. Along the way, my talk will touch on non-equilibrium fluctuations, "violations" of the second law, the thermodynamic arrow of time, nanoscale feedback control, strong system-environment coupling, and quantum thermodynamics.
	Host	BingKan Xue

February 25
	Speaker	Lisa Larrimore Ouellette, Stanford University
	Title	Should Physicists Care About Patent Law?
	Abstract	Academic science has become increasingly entwined with patent law in recent decades, with U.S. universities receiving over 5000 patents per year and bringing in billions of dollars in licensing income. But surprisingly little is known about how patents affect university research. Do scientists learn anything from the technical disclosures in patents? Could patents be improved by scientific peer review? How do the financial incentives from patents affect academic scientists? This lecture will describe my empirical research on these questions—drawn from my background as both a Ph.D. physicist and a lawyer—including survey results, a three-year randomized controlled field experiment on patent peer review, and a study of variation in patent royalty-sharing policies across universities.
	Host	Kathryn McGill

March 4
	Speaker
	Title
	Abstract
	Host

March 11
	Speaker	Eduardo Fradkin, University of Illinois
	Title	TBA
	Abstract
	Host	Yuxuan Wang

March 18
	Speaker	Amandine Aftalion, CNRS senior scientist, Ecole des Hautes Etudes en sciences sociales, Paris, France
	Title	Modelling of Racing
	Abstract	In order to determine the optimal strategy to run a race according to the distance to run, we introduce a model based on a system of differential equations for the velocity, the propulsive force and the anaerobic energy. The system does not rely on statistics but couples mechanics, energetics (both aerobic and anaerobic), neural drive to an economic decision theory of cost and benefit. For a fixed distance to run (from 100m to 10 000m), we find how effort is minimized to produce the best running strategy. This takes into account the effect of the bend, of the lane and the psychological interaction with a neighbor on the next lane. We even suggest how present tracks could be modified to improve record times and decrease discrepancy between lanes.
	Host

March 25
	Speaker	Reserved for faculty search
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	Abstract
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April 1
	Speaker	Reserved for faculty search
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April 8
	Speaker	Reserved for faculty search
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	Abstract
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April 15
	Speaker	Reserved for faculty search
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	Abstract
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April 22
	Speaker	Clifford Will, UF Physics
	Title	Einstein Prize Talk
	Abstract
	Host	David Tanner