No-signaling Principle Can Determine Optimal Quantum State Discrimination

TL;DR

This paper demonstrates that the no-signaling principle can be used to determine the optimal guessing probability in quantum state discrimination, linking fundamental physics constraints to quantum information tasks.

Contribution

It introduces a framework connecting the no-signaling principle with the derivation of optimal quantum state discrimination probabilities, providing a new perspective on quantum measurement limits.

Findings

Guessing probability can be derived from no-signaling constraints.

Optimality conditions align with no-superluminal communication constraints.

A closed-form bound for guessing probability is established.

Abstract

We provide a general framework of utilizing the no-signaling principle in derivation of the guessing probability in the minimum-error quantum state discrimination. We show that, remarkably, the guessing probability can be determined by the no-signaling principle. This is shown by proving that in the semidefinite programming for the discrimination, the optimality condition corresponds to the constraint that quantum theory cannot be used for a superluminal communication. Finally, a general bound to the guessing probability is presented in a closed form.