Amplifying quantum correlations with quench dynamics in a quantum spin chain: Steady-states versus ground-states

TL;DR

This paper investigates how quench dynamics in quantum spin chains can significantly enhance steady-state quantum correlations beyond ground-state levels, revealing nonanalyticities linked to quantum phase transitions and offering practical control protocols.

Contribution

It introduces and analyzes single and double quench protocols to amplify steady-state quantum correlations in spin chains, connecting nonequilibrium dynamics with quantum phase transition signatures.

Findings

Steady-state quantum correlations surpass ground-state correlations after quenches.

Double quench dynamics can further enhance quantum correlations.

Nonanalyticities in correlations indicate nonequilibrium quantum phase transitions.

Abstract

We analyze the behavior of steady-state quantum correlations (QCs) in the spin-1/2 transverse field XY chains analytically, in terms of quench dynamics at zero-temperature. We show that steady-state QCs are strikingly greater than the equilibrium ones in its ground-state, where a single quench is performed from ferro- into para-magnetic phases. Another framework to amplify the QCs here is a feasible protocol called double quench dynamics. To fulfill this purpose, we probe a middle quench point and spending time T (defined as the time passing from the middle quench point before reaching a second quench). By doing so, both single and double quenches act as practical tools to control the enhancement of the steady-state QCs in the final quenched point. In particular, and in parallel to expectations for some other quantities, we indicate that the nonequilibrium quantum phase transitions also can be identified by nonanalyticities in the steady-state QCs. Our work may be testable with the current class of trapped-ion or ultracold-atom experiments, and encourage the possible potential in the quantum information field.