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Universal Long-Time Behavior of the Quantum Fisher Information in Dynamical Quantum Phase Transitions
J. Mumford, R. J. Lewis-Swan
https://arxiv.org/abs/2507.05579

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