Signatures of quantum phase transitions after quenches in quantum chaotic one-dimensional systems

Asmi Haldar, Krishnanand Mallayya, Markus Heyl, Frank Pollmann, Marcos Rigol, Arnab Das

Published 2020-04-06Version 1

Quantum phase transitions are central for the understanding of the equilibrium low-temperature properties of quantum matter. Locating them can be challenging both by means of theoretical techniques as well as for experiments. Here, we show that the antithetic strategy of forcing a system strongly out of equilibrium can provide a route to identify signatures of quantum phase transitions. By quenching a quantum chaotic (nonintegrable) spin chain, we find that local observables can exhibit distinct features in their intermediate-time dynamics, when the quench parameter is close to its critical value, where the ground state undergoes a quantum phase transition. We find that the effective temperature in the expected thermal-like states after equilibration exhibits a minimum in the vicinity of the quantum critical value of the quench parameter, correlating with the features in the real-time dynamics of observables. We also explore dynamical nonequilibrium signatures of a quantum critical point in a model with a topological transition, and discuss how to access our results experimentally in systems of Rydberg atoms.