Evaporative cooling and self-thermalization in an open system of interacting fermions

Abstract

We study depletion dynamics of an open system of weakly interacting fermions with two-body random interactions. In this model fermions are escaping from the high-energy one-particle orbitals, that mimics the evaporation process used in laboratory experiments with neutral atoms to cool them to ultra-low temperatures. It is shown that due to dynamical thermalization the system instantaneously adjusts to the new chemical potential and temperature, so that occupation numbers of the one-particle orbitals always obey the Fermi-Dirac distribution. In this way we are able to describe the evaporation process which leads to a significant cooling of particles remaining inside the system. We also briefly discuss the evaporation process in the SYK black hole model that corresponds to strongly interacting fermions.