Parameter estimation using NOON states over a relativistic quantum channel

TL;DR

This paper investigates how an observer's acceleration affects parameter estimation using NOON states in a relativistic quantum channel, revealing counter-intuitive encoding performance and optimal photon number dependencies.

Contribution

It analyzes the impact of acceleration on quantum Fisher information for NOON states, highlighting the superiority of single rail encoding and the existence of an optimal photon number.

Findings

Single rail encoding outperforms dual rail under acceleration.

Optimal N decreases as acceleration increases.

Quantum Fisher information is affected by relativistic effects.

Abstract

We study the effect of the acceleration of the observer on a parameter estimation protocol using NOON states. An inertial observer, Alice, prepares a NOON state in Unruh modes of the quantum field, and sends it to an accelerated observer, Rob. We calculate the quantum Fisher information of the state received by Rob. We find the counter-intuitive result that the single rail encoding outperforms the dual rail. The NOON states have an optimal $N$ for the maximum information extractable by Rob, given his acceleration. This optimal $N$ decreases with increasing acceleration.