Abstract

To most efficiently estimate a parameter of a quantum system, one needs to choose the optimal measurement that creates the conditions for the most efficient estimator to act. Specifically, one needs to implement the measurement that achieves the quantum Fisher information (qFi) for that particular estimation task. In this work, we search for an optimal measurement for estimating the coherence, parameterised as η, of a mixed state composed of coherent light and thermal (incoherent) light. Our search is limited to photon-starved signals, with signal strength of n bar<< 1. We found that the classical choice of measurement, direct detection, was suboptimal, whereas homodyne detection approached the qFi for estimating coherence for the low coherence (η~ 0) range.

Date

November 1, 2025

Authors

Zi Chua, Jonathan Habif, Federico Spedalieri

Journal

APS March Meeting Abstracts

Volume

2021

Pages

B32. 013