Effects of Phase Fluctuations on Phase Sensitivity and Visibility of Path-Entangled Photon Fock States

TL;DR

This paper compares the robustness of mm' and N00N path-entangled photon states under phase fluctuations like turbulence noise, showing both achieve optimal phase sensitivity with parity detection despite the noise.

Contribution

It demonstrates that mm' states are as effective as N00N states under phase fluctuations and confirms parity detection as an optimal measurement strategy in noisy environments.

Findings

mm' states are more robust against photon loss and perform similarly to N00N states under phase fluctuations.

Phase sensitivity with parity detection saturates the quantum Cramer-Rao bound for both states in noisy conditions.

Parity detection is confirmed as an optimal strategy for phase measurement in the presence of realistic phase noise.

Abstract

We study effects of phase fluctuations on phase sensitivity and visibility of a class of robust path-entangled photon Fock states (known as mm' states) as compared to the maximally path-entangled N00N states in presence of realistic phase fluctuations such as turbulence noise. Our results demonstrate that the mm' states, which are more robust than the N00N state against photon loss, perform equally well when subject to such fluctuations. We show that the phase sensitivity with parity detection for both of the above states saturates the quantum Cramer-Rao bound in presence of such noise, suggesting that the parity detection presents an optimal detection strategy.