The quantum adiabatic theorem governs the evolution of a wavefunction under a slowly time-varying Hamiltonian. I will consider the opposite limit of a Hamiltonian that is varied impulsively: an infinitely strong perturbation U(x,t) is applied over an infinitesimal time interval. When the strength and duration of the perturbation scale appropriately, the impulse causes the wavefunction y(x,t) to undergo a sudden displacement and/or deformation. Remarkably, this evolution is described by a purely classical construction. I will use these results to show how tailored impulses can be used to control the behavior of a quantum wavefunction, in one or more degrees of freedom.
Christopher Jarzynski received his A.B. (with high honors) in 1987 from Princeton University and his Ph.D. in 1994 from University of California, Berkeley. His research focuses on statistical mechanics and thermodynamics at the molecular level, with a particular focus on the foundations of nonequilibrium thermodynamics. His research group has worked on topics that include the application of statistical mechanics to problems of biophysical interest; the analysis of artificial molecular machines; the development of efficient numerical schemes for estimating thermodynamic properties of complex systems; the relationship between thermodynamics and information processing; quantum and classical shortcuts to adiabaticity; and quantum thermodynamics. Jarzynski is a Fellow of the American Physical Society and the American Academy of Arts and Sciences, and the recipient of the 2019 Lars Onsager Prize for theoretical statistical physics. He is a UMD Distinguished University Professor.