Effect of double local quenches on Loschmidt echo and entanglement entropy of a one-dimensional quantum system

TL;DR

This paper investigates how two simultaneous local quenches affect the evolution of Loschmidt echo and entanglement entropy in a one-dimensional transverse Ising model, revealing complex dynamics and timescales.

Contribution

It introduces a numerical study of double local quenches in a quantum spin chain, analyzing their impact on quantum coherence and entanglement evolution.

Findings

Double quenches induce distinct dynamical regimes in Loschmidt echo.

Entanglement entropy exhibits characteristic growth patterns post-quench.

Quasiparticle picture explains timescales and dynamical features observed.

Abstract

We study the effect of two simultaneous local quenches on the evolution of Loschmidt echo and entanglement entropy of a one dimensional transverse Ising model. In this work, one of the local quenches involves the connection of two spin-1/2 chains at a certain time and the other local quench corresponds to a sudden change in the magnitude of the transverse field at a given site in one of the spin chains. We numerically calculate the dynamics associated with the Loschmidt echo and the entanglement entropy as a result of such double quenches, and discuss various timescales involved in this problem using the picture of quasiparticles generated as a result of such quenches.