Quantum state discrimination

TL;DR

This paper reviews the fundamental challenge of distinguishing non-orthogonal quantum states, discussing optimal discrimination strategies and experimental realizations in optics.

Contribution

It provides a comprehensive review of strategies and experiments for optimal quantum state discrimination, highlighting recent advances and practical implementations.

Findings

Optimal discrimination strategies for non-orthogonal states

Experimental optical realizations of quantum state discrimination

Insights into the limits imposed by quantum mechanics

Abstract

It is a fundamental consequence of the superposition principle for quantum states that there must exist non-orthogonal states, that is states that, although different, have a non-zero overlap. This finite overlap means that there is no way of determining with certainty in which of two such states a given physical system has been prepared. We review the various strategies that have been devised to discriminate optimally between non-orthogonal states and some of the optical experiments that have been performed to realise these.