Equilibration time scales in closed many-body quantum systems. (29th March 2018)

• Record Type: Journal Article
• Authors: de Oliveira, Thiago R; Charalambous, Christos; Jonathan, Daniel; Lewenstein, Maciej; Riera, Arnau
• Is Part Of: New journal of physics. Volume 20:Number 3(2018:Mar.)
• Publication Date: 2018-03-29
• Subjects: equilibration -- unitary dynamics -- quantum systems -- foundations of statistical mechanics; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aab03b
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: We show that the physical mechanism for the equilibration of closed quantum systems is dephasing, and identify the energy scales that determine the equilibration timescale of a given observable. For realistic physical systems (e.g those with local Hamiltonians), our arguments imply timescales that do not increase with the system size, in contrast to previously known upper bounds. In particular we show that, for such Hamiltonians, the matrix representation of local observables in the energy basis is banded, and that this property is crucial in order to derive equilibration times that are non-negligible in macroscopic systems. Finally, we give an intuitive interpretation to recent theorems on equilibration time-scales.