Dynamical phase transitions, time-integrated observables and geometry of states

TL;DR

This paper demonstrates the existence of dynamical phase transitions in the transverse-field Ising model away from static critical points, linking these to geometric properties of special initial states.

Contribution

It reveals dynamical phase transitions in the TFIM linked to special states with geometric features akin to static critical points, extending understanding beyond static criticality.

Findings

DPTs occur away from static quantum critical points.

Special states exhibit geometric features similar to static critical points.

Temporal non-analyticities in return probability indicate DPTs.

Abstract

We show that there exist dynamical phase transitions (DPTs), as defined in [Phys. Rev. Lett. 110 135704 (2013)], in the transverse-field Ising model (TFIM) away from the static quantum critical points. We study a class of special states associated with singularities in the generating functions of time-integrated observables found in [Phys. Rev. B 88 184303 (2013)]. Studying the dynamics of these special states under the evolution of the TFIM Hamiltonian, we find temporal non-analtyicities in the initial-state return probability associated with dynamical phase transitions. By calculating the Berry phase and Chern number we show the set of special states have interesting geometric features similar to those associated with static quantum critical points.