Tradeoff between energy and error in the discrimination of quantum-optical devices

TL;DR

This paper investigates the energy-error tradeoff in discriminating two quantum optical devices, deriving optimal strategies and showing that these outperform simpler methods in energy efficiency.

Contribution

It provides an analytical solution for optimal discrimination strategies and an iterative algorithm for general cases, highlighting energy savings over simpler techniques.

Findings

Optimal strategy requires less energy for the same performance.

Analytical derivation for beamsplitters.

Iterative algorithm converges to the optimal solution.

Abstract

We address the problem of energy-error tradeoff in the discrimination between two linear passive quantum optical devices with a single use. We provide an analytical derivation of the optimal strategy for beamsplitters and an iterative algorithm converging to the optimum in the general case. We then compare the optimal strategy with a simpler strategy using coherent input states and homodyne detection. It turns out that the former requires much less energy in order to achieve the same performances.