Adiabatic quenches through an extended quantum critical region

TL;DR

This paper investigates defect formation in a quantum XXZ chain during adiabatic quenches across an extended critical region, analyzing different quench paths and comparing results with established theories.

Contribution

It introduces a detailed numerical study of defect formation during quenches through an extended critical region in a quantum spin chain, comparing dynamical scalings with theoretical predictions.

Findings

Residual energy scales with quench rate as predicted by Kibble-Zurek theory.

Different quench paths exhibit distinct dynamical scaling behaviors.

Time-dependent DMRG effectively captures non-adiabatic effects in quantum critical quenches.

Abstract

By gradually changing the degree of the anisotropy in a XXZ chain we study the defect formation in a quantum system that crosses an extended critical region. We discuss two qualitatively different cases of quenches, from the antiferromagnetic to the ferromagnetic phase and from the critical to the antiferromegnetic phase. By means of time-dependent DMRG simulations, we calculate the residual energy at the end of the quench as a characteristic quantity gauging the loss of adiabaticity. We find the dynamical scalings of the residual energy for both types of quenches, and compare them with the predictions of the Kibble-Zurek and Landau-Zener theories.