Optimal Quantum States for Image Sensing in Loss

TL;DR

This paper identifies optimal quantum states for image sensing under loss, demonstrating that pure states with specific photon number distributions minimize sensing cost in various scenarios.

Contribution

It introduces a general framework for quantum image sensing and proves the optimality of certain pure states under loss and energy constraints.

Findings

Pure states with mixed number states minimize sensing cost.

Optimal states are identified for lossy binary phase discrimination.

Framework applies to general lossless image sensing scenarios.

Abstract

We consider a general image sensing framework that includes many quantum sensing problems by an appropriate choice of image set, prior probabilities, and cost function. For any such problem, in the presence of loss and a signal energy constraint, we show that a pure input state of light with the signal modes in a mixture of number states minimizes the cost among all ancilla-assisted parallel strategies. Lossy binary phase discrimination with a peak photon number constraint and general lossless image sensing are considered as examples.