Unambiguous discrimination of Fermionic states through local operations and classical communication

TL;DR

This paper investigates the limits of unambiguous discrimination of Fermionic states using local operations and classical communication, revealing fundamental differences from quantum state discrimination and proposing a method to reach optimal success probabilities.

Contribution

It demonstrates that unambiguous discrimination of Fermionic states via LOCC is generally limited but can be improved with an ancillary entangled Fermionic system.

Findings

LOCC cannot always match global measurement success probabilities for Fermionic states

An ancillary maximally entangled Fermionic system enables optimal discrimination success

The results hold regardless of the system's dimension

Abstract

The paper studies unambiguous discrimination of Fermionic states through local operations and classical communication (LOCC). In the task of unambiguous discrimination, no error is tolerated but an inconclusive result is allowed. We show that contrary to the quantum case, it is not always possible to distinguish two Fermionic states through LOCC unambiguously with the same success probability as if global measurements were allowed. Furthermore, we prove that we can overcome such a limit through an ancillary system made of two Fermionic modes, independently of the dimension of the system, prepared in a maximally entangled state: in this case, LOCC protocols achieve the optimal success probability.