Theory of defect production in nonlinear quench across a quantum critical point

TL;DR

This paper analyzes how defect density scales with quench rate and exponent in nonlinear quantum quenches across critical points, providing detailed theoretical predictions for defect correlations and experimental relevance.

Contribution

It extends previous work by providing a detailed analysis of defect scaling and correlations in nonlinear quenches through quantum critical points and lines.

Findings

Defect density scales with quench rate and exponent as predicted.

Correlation functions depend on the nonlinear quench exponent.

Theoretical predictions applicable to various experimental systems.

Abstract

We study defect production in a quantum system subjected to a nonlinear power law quench which takes it either through a quantum critical or multicritical point or along a quantum critical line. We elaborate on our earlier work [D. Sen, K. Sengupta, S. Mondal, \prl 101, 016806 (2008)] and present a detailed analysis of the scaling of the defect density $n$ with the quench rate $\tau$ and exponent $\al$ for each of the above-mentioned cases. We also compute the correlation functions for defects generated in nonlinear quenches through a quantum critical point and discuss the dependence of the amplitudes of such correlation functions on the exponent $\al$. We discuss several experimental systems where these theoretical predictions can be tested.