Coherence revival under the Unruh effect and its metrological advantage

Source abstract

Abstract In this paper, we investigate the quantum coherence extraction between two accelerating Unruh–DeWitt detectors, coupling to a scalar field in (3 + 1)-dimensional Minkowski spacetime. We find that quantum coherence as a nonclassical correlation can be generated through the Markovian evolution of the detector system, just like quantum entanglement. However, with growing Unruh temperature, in contrast to monotonously degrading entanglement, we find that quantum coherence exhibits a striking revival phenomenon. For certain detectors’ initial state choices, the coherence measure will reduce to zero at first and then grow to an asymptotic value. We verify such coherence revival by inspecting its metrological advantage on the quantum Fisher information (QFI) enhancement. Since the maximal QFI bounds the accuracy of quantum parameter estimation, we conclude that the extracted coherence can be utilized as a physical resource in quantum metrology.