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arXiv · 1404.7110

Quantum correlations in optical metrology: Heisenberg-limited phase estimation without mode entanglement

Jaspreet Sahota·Nicolás Quesada
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Abstract

The quantum fisher information and quantum correlation parameters are employed to study the application of non-classical light to the problem of parameter estimation. It is shown that the optimal measurement sensitivity of a quantum state is determined by its inter-mode correlations (which depends of path-entanglement) and intra-mode correlations (which depends of the photon statistics). In light of these results, we consider the performance of quantum-enhanced optical interferometers. Furthermore, we propose a Heisenberg-limited metrology protocol involving standard elements from passive and active linear optics, for which the quantum Cramér-Rao bound is saturated with an intensity measurement. Interestingly, the quantum advantage for this scheme is derived solely from the non-classical photon statistics of the probe state and does not depend of entanglement. We study the performance of this scheme in the presence of realistic losses and consequently predict a substantial enhancement over the shot-noise limit with current technological capabilities.

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Jaspreet Sahota, Nicolás Quesada. 2015-01-08. Quantum correlations in optical metrology: Heisenberg-limited phase estimation without mode entanglement. https://doi.org/10.1103/physreva.91.013808

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