Quantum Fisher Information of Entangled Coherent States in a Lossy Mach-Zehnder Interferometer

TL;DR

This paper derives an analytical expression for the quantum Fisher information of entangled coherent states in a lossy Mach-Zehnder interferometer, showing potential to surpass the Heisenberg limit in phase sensitivity.

Contribution

It provides a new analytical framework for evaluating phase sensitivity of entangled coherent states under photon loss conditions.

Findings

Entangled coherent states can surpass the Heisenberg limit with small photon loss.

The formalism applies to multipartite entangled coherent states.

Analytical results enhance understanding of quantum phase estimation in lossy systems.

Abstract

We give an analytical result for the quantum Fisher information of entangled coherent States in a lossy Mach-Zehnder Interferometer recently proposed by J. Joo et al. [Phys. Rev. Lett. 107, 083601(2011)]. For small loss of photons, we find that the entangled coherent state can surpass the Heisenberg limit. Furthermore, The formalism developed here is applicable to the study of phase sensitivity of multipartite entangled coherent states.