Identifying and harnessing dynamical phase transitions for quantum-enhanced sensing

Abstract

We propose the quantum Fisher information (QFI) as a tool to characterize dynamical phase transitions in closed quantum systems, which are usually defined in terms of non-analytic behaviour of a time-averaged order parameter. Employing the Lipkin-Meshkov-Glick model as an illustrative example, we predict that DPTs correlate with a divergent peak in the QFI that indicates the presence of correlations and entanglement useful for quantum metrology. We discuss a simple analytic model that connects the scaling of the QFI to the behaviour of the order parameter and propose a robust interferometric protocol that can enable DPTs to be harnessed as the basis of quantum-enhanced sensors.