Irreversibility and the arrow of time in a quenched quantum system
Abstract
Irreversibility is one of the most intriguing concepts in physics. While microscopic physical laws are perfectly reversible, macroscopic average behavior has a preferred direction of time. According to the second law of thermodynamics, this arrow of time is associated with a positive mean entropy production. Using a nuclear magnetic resonance setup, we measure the nonequilibrium entropy produced in an isolated spin-1/2 system following fast quenches of an external magnetic field and experimentally demonstrate that it is equal to the entropic distance, expressed by the Kullback-Leibler divergence, between a microscopic process and its time-reverse. Our result addresses the concept of irreversibility from a microscopic quantum standpoint.
Keywords
Cite
@article{arxiv.1502.06704,
title = {Irreversibility and the arrow of time in a quenched quantum system},
author = {T. B. Batalhao and A. M. Souza and R. S. Sarthour and I. S. Oliveira and M. Paternostro and E. Lutz and R. M. Serra},
journal= {arXiv preprint arXiv:1502.06704},
year = {2017}
}
Comments
8 pages, 7 figures, RevTeX4-1; Accepted for publication Phys. Rev. Lett