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

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.