Quantum relaxation after a quench in systems with boundaries

TL;DR

This paper investigates the dynamic relaxation processes of a quantum Ising chain with boundaries after a quench, revealing cyclic magnetization behavior, non-thermal surface effects, and a novel time-scale during reconstruction.

Contribution

It introduces a detailed analysis of boundary effects and identifies a new time-scale in the relaxation dynamics of quantum spin chains post-quench.

Findings

Magnetization exhibits cyclic variation with quasi-stationary and reconstruction phases.

Surface sites show non-thermal behavior, while bulk sites thermalize.

Discovery of a non-standard time-scale during the reconstruction period.

Abstract

We study the time-dependence of the magnetization profile, m_l(t), of a large finite open quantum Ising chain after a quench. We observe a cyclic variation, in which starting with an exponentially decreasing period the local magnetization arrives to a quasi-stationary regime, which is followed by an exponentially fast reconstruction period. The non-thermal behavior observed at near-surface sites turns over to thermal behavior for bulk sites. Besides the standard time- and length-scales a non-standard time-scale is identified in the reconstruction period.