Entanglement-enhanced testing of multiple quantum hypotheses

TL;DR

This paper demonstrates that entangled photons significantly improve the ability to distinguish among multiple quantum channels, extending quantum hypothesis testing beyond binary cases and enabling advanced technological applications.

Contribution

It introduces a general framework for multi-channel discrimination using entangled photons, surpassing classical strategies and broadening quantum hypothesis testing capabilities.

Findings

Entangled photons outperform classical strategies in multi-channel discrimination.

The approach applies to optical data readout, spectroscopy, and target localization.

Entanglement enhances quantum hypothesis testing beyond binary scenarios.

Abstract

Quantum hypothesis testing has been greatly advanced for the binary discrimination of two states, or two channels. In this setting, we already know that quantum entanglement can be used to enhance the discrimination of two bosonic channels. Here, we remove the restriction of binary hypotheses and show that entangled photons can remarkably boost the discrimination of multiple bosonic channels. More precisely, we formulate a general problem of channel-position finding where the goal is to determine the position of a target channel among many background channels. We prove that, using entangled photons at the input and a generalized form of conditional nulling receiver at the output, we may outperform any classical strategy. Our results can be applied to enhance a range of technological tasks, including the optical readout of sparse classical data, the spectroscopic analysis of a frequency spectrum, and the determination of the direction of a target at fixed range.