Guest Speaker – Physical (CHEM 781) – April 12, 2023

Bio
Todd Gingrich is an Assistant Professor of Chemistry at Northwestern University. Todd studied physical chemistry at Caltech (B.S., 2008), at Oxford as a Rhodes Scholar (M.Sc., 2010), and finally at the University of California, Berkeley as an NSF and Hertz Fellow (Ph.D., 2015). As a Physics of Living Systems Fellow at MIT, Todd derived the Thermodynamic Uncertainty Relationship for nonequilibrium systems. That collaborative work with Jordan Horowitz was recognized in 2019 by the American Physical Society with the Irwin Oppenheim Award. His research program at Northwestern has been recognized with an NSF CAREER award and a Sloan Fellowship. Equally important, Todd is a passionate teacher, who has earned recognition for courses that range from freshman general chemistry through graduate statistical mechanics.

Abstract
Chemical systems can deviate from equilibrium for a variety of reasons: because they are kinetically trapped, because they are subject to a time-varying drive, or because they are simultaneously in contact with multiple incommensurate reservoirs. This last scenario, which generates a nonequilibrium steady state (NESS), yields a stationary distribution over microstates that is not Boltzmann and that sustains currents. I will discuss three parallel efforts to better understand the chemical dynamics of such steady states. First, I will introduce a thermodynamic uncertainty relationship constraining the magnitude of fluctuations in currents. Next, I will discuss my group’s efforts to elucidate structure-function relationships in model molecular motors by simulating the NESS with a mixture of Langevin dynamics and Grand Canonical Monte Carlo chemostats. Finally, I will show how tensor network methods, popular in physics literature for quantum dynamics of spin chains, can be repurposed to compute rates for nonequilibrium reaction-diffusion processes.