Universal Long-Time Behavior of the Quantum Fisher Information in Dynamical Quantum Phase Transitions

TL;DR

This paper studies the long-time behavior of quantum Fisher information during dynamical quantum phase transitions in systems with classical limits, revealing universal patterns across different models.

Contribution

It introduces the use of long-time average quantum Fisher information as a universal diagnostic for dynamical quantum phase transitions in various systems.

Findings

QFI abruptly changes at the transition point

Long-time average QFI exhibits universal behavior

Results hold across different models like BEC and LMG

Abstract

We investigate dynamical quantum phase transitions (DQPTs) in quantum systems that possess well-defined classical limits, focusing on the spinor Bose-Einstein condensate and the Lipkin-Meshkov-Glick model. We diagnose the DQPTs with the long-time average of the quantum Fisher information (QFI) showing that it abruptly changes at the transition point. Using mean-field and semiclassical approximations, we demonstrate that the long-time average of the QFI reveals universal behavior that persists across different systems.