Lossy Quantum Optical Metrology with Squeezed States

TL;DR

This paper analyzes the impact of photon losses on quantum phase estimation using squeezed states, providing exact quantum Fisher information calculations and optimized measurement strategies to enhance practical quantum metrology.

Contribution

It offers the first exact quantum Fisher information analysis for lossy squeezed-state metrology and proposes optimized phase shifts and resource strategies for experimental realization.

Findings

Quantum enhancement persists despite photon losses.

Parity measurement schemes are less effective with small losses unless optimized.

Optimized phase shifts improve measurement precision.

Abstract

We study the precise phase estimation using squeezed states with photon losses present. Our exact quantum Fisher information calculation shows significant quantum enhancement and thus reveals the benchmark for practical quantum metrology in this noisy scenario. However, we find that the existing parity measurement scheme [P.M. Anisimov et al, Phys. Rev. Lett. 104, 103602 (2010)] behaves worse than even classical cases given very small losses, unless we take an appropriate loss dependent phase shift. Using our formulae, the two optimized aspects including the pre-detection phase shift and the consequent light intensity of a tradeoff strategy for photon resource arrangement can be both calculated. Therefore our result makes it possible to experimentally realize quantum metrology of phase estimation with squeezed states.