Identifying and harnessing dynamical phase transitions for quantum-enhanced sensing
Abstract
We use the quantum Fisher information (QFI) to diagnose a dynamical phase transition (DPT) in a closed quantum system, which is 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 find that the DPT correlates with a peak in the QFI that can be explained by a generic connection to an underlying excited-state quantum phase transition that also enables us to also relate the scaling of the QFI with the behaviour of the order parameter. Motivated by the QFI as a quantifier of metrologically useful correlations and entanglement, we also present a robust interferometric protocol that can enable DPTs as a platform for quantum-enhanced sensing.
Cite
@article{arxiv.2103.13418,
title = {Identifying and harnessing dynamical phase transitions for quantum-enhanced sensing},
author = {Qingze Guan and Robert J. Lewis-Swan},
journal= {arXiv preprint arXiv:2103.13418},
year = {2021}
}
Comments
3 Figures and 5 pages in the main text; 7 pages and 6 figures in the appendix