Optimality of minimum-error discrimination by the no-signalling condition

TL;DR

This paper derives the minimum error in discriminating two quantum states by linking the no-signalling condition to the fundamental limits of quantum state discrimination.

Contribution

It establishes a connection between the no-signalling principle and the optimality of minimum-error quantum state discrimination.

Findings

Derived the minimum error bound using no-signalling

Linked no-go theorems to discrimination limits

Provided a physical principle-based derivation

Abstract

In this work we relate the well-known no-go theorem that two non-orthogonal (mixed) quantum states cannot be perfectly discriminated, to the general principle in physics, the no-signalling condition. In fact, we derive the minimum error in discrimination between two quantum states, using the no-signalling condition.