Factorizability of multi-party quantum sequence discrimination under local operations and classical communication

TL;DR

This paper investigates conditions under which multi-party quantum sequence discrimination can be simplified into independent steps, revealing when optimal local operations and classical communication can be factorized for efficiency.

Contribution

It establishes necessary and sufficient conditions for factorizing optimal LOCC discrimination in multi-party quantum sequences, advancing understanding of quantum data hiding limits.

Findings

Factorizability of optimal LOCC discrimination is possible under certain conditions.

Optimal discrimination can sometimes be achieved by guessing the most probable state.

Provides examples illustrating when factorization of discrimination is feasible.

Abstract

We consider multi-party quantum sequence discrimination under local operations and classical communication(LOCC), and provide conditions under which the optimal LOCC discrimination of a multi-party quantum sequence ensemble can be factorized into that of each individual ensemble. In other words, the optimal LOCC discrimination of a multi-party quantum sequence ensemble can be achieved just by performing optimal LOCC discrimination independently at each step of the quantum sequence. We also illustrate through examples of multi-party quantum states that such factorizability of optimal LOCC discrimination is possible. We further establish a necessary and sufficient condition under which the optimal LOCC discrimination of a multi-party quantum state ensemble can be realized just by guessing the state with the largest probability. Our results can provide a useful application to investigate the fundamental limits of quantum data hiding.