Compelling Bounds on Equilibration Times -- the Issue with Fermi's Golden Rule
arXiv:1910.13262 · doi:10.1088/1751-8121/ab9e2b
Abstract
Putting a general, physically relevant upper bound on equilibration times in closed quantum systems is a recently much pursued endeavor. In PRX, 7, 031027 (2017) Garc\'ıa-Pintos et al. suggest such a bound. We point out that the general assumptions which allow for an actual estimation of this bound are violated in cases in which Fermi's Golden Rule and related open quantum system theories apply. To probe the range of applicability of Fermi's Golden Rule for systems of the type addressed in the above work, we numerically solve the corresponding Schrödinger equation for some finite spin systems comprising up to 25 spins. These calculations shed light on the breakdown of standard quantum master equations in the "superweak" coupling limit, which occurs for finite sized baths.
10 pages, 9 figures
References in corpus (8)
- Foundation of Statistical Mechanics under experimentally realistic conditions
- Exact relaxation in a class of non-equilibrium quantum lattice systems
- Typicality for Generalized Microcanonical Ensembles
- Thouless and relaxation time scales in many-body quantum systems
- Diverging equilibration times in long-range quantum spin models
- Dynamical typicality of isolated many-body quantum systems
- Why are macroscopic experiments reproducible? Imitating the behavior of an ensemble by single pure states
- Mechanism of slow equilibration of isolated quantum systems