Dynamical phase transitions after quenches in non-integrable models

TL;DR

This paper demonstrates that non-analytic dynamical phase transitions occur after sudden quenches across quantum critical points in non-integrable models, extending previous findings from exactly solvable systems to more complex, interacting theories.

Contribution

It shows that dynamical phase transitions are a generic feature in non-integrable quantum models, broadening the understanding beyond free-fermion systems.

Findings

Non-analytic behavior in the rate function after quenches

Dynamical phase transitions occur in non-integrable models

Results suggest universality of dynamical phase transitions

Abstract

We investigate the dynamics following sudden quenches across quantum critical points belonging to different universality classes. Specifically, we use matrix product state methods to study the quantum Ising chain in the presence of two additional terms which break integrability. We find that in all models the rate function for the return probability to the initial state becomes a non-analytic function of time in the thermodynamic limit. This so-called `dynamical phase transition' was first observed in a recent work by Heyl, Polkovnikov, and Kehrein [Phys. Rev. Lett. 110, 135704 (2013)] for the exactly-solvable quantum Ising chain, which can be mapped to free fermions. Our results for `interacting theories' indicate that non-analytic dynamics is a generic feature of sudden quenches across quantum critical points. We discuss potential connections to the dynamics of the order parameter.