Two-step relaxation in local many-body Floquet systems

Abstract

We want to understand how relaxation process from an initial non-generic state proceeds towards a long-time typical state reached under unitary quantum evolution. One would expect that after some initial correlation time relaxation will be a simple exponential decay with constant decay rate. We show that this is not necessarily the case. Studying various Floquet systems with fixed two-qubit gates, and focusing on purity and out-of-time-ordered correlation functions, we find that in many situations relaxation proceeds in two phases of exponential decay having different relaxation rates. Namely, in the thermodynamic limit the relaxation rate exhibits a change at a critical time proportional to system's size. The initial thermodynamically relevant rate can be slower or faster than the asymptotic one, demonstrating that the recently discovered phantom relaxation, in which the decay is slower than predicted by a nonzero transfer matrix gap, is not limited to only random circuits.

Keywords

statistična fizika;kvantna mehanika;statistical physics;quantum mechanics;Floquet systems;complexity dynamics;

Data

Language:	English
Year of publishing:	2023
Typology:	1.01 - Original Scientific Article
Organization:	UL FMF - Faculty of Mathematics and Physics
UDC:	536.93
COBISS:	188707331
ISSN:	1751-8113
Views:	37
Downloads:	5
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	Slovenian
Secondary keywords:	statistična fizika;kvantna mehanika;
Type (COBISS):	Article
Pages:	14 str.
Volume:	ǂVol. ǂ56
Issue:	ǂno. ǂ43, art. no. 434001
Chronology:	Oct. 2023
DOI:	10.1088/1751-8121/acfc05
ID:	23133362