Physics Colloquium: New Horizons in Physics From Open Quantum Systems

Abstract: One of the first rules we learn in quantum mechanics is that, when sequestered, systems undergo evolution obtained by solving the Schrödinger equation.  This ensures that probability is conserved, and that one obtains sensible statistical predictions for repeated experiments.  Most systems, however, are coupled to environments that are difficult or perhaps impossible to access.  For example, quantum computation must be done in a low, but finite temperature bath.  More exotically, black hole horizons, or the edge of the observable universe are effectively “points of no return” for portions of physical systems storing quantum information.  An understanding of “open” quantum theories is thus essential for  resolving engineering issues, and perhaps to address long-standing questions in particle physics and cosmology.  After first motivating the study of open systems with discussions of such problems, I will go into some specific, and relatively simple examples of low dimensional open quantum systems, some of which are amenable to simulation on current and near-term quantum hardware.