Experimental Quantum Process Discrimination

TL;DR

This paper demonstrates experimentally that non-orthogonal quantum processes can be unambiguously discriminated with high confidence using entanglement and advanced measurement techniques, advancing quantum information processing capabilities.

Contribution

It provides the first experimental demonstration of unambiguous deterministic quantum process discrimination for non-orthogonal processes, including multipartite unitaries.

Findings

Discrimination confidence $ ext{≥}97 ext{%}$ for all tested cases

Successful discrimination of single-qubit and multipartite unitaries

Use of entanglement and higher-dimensional systems enhances discrimination

Abstract

Discrimination between unknown processes chosen from a finite set is experimentally shown to be possible even in the case of non-orthogonal processes. We demonstrate unambiguous deterministic quantum process discrimination (QPD) of non-orthogonal processes using properties of entanglement, additional known unitaries, or higher dimensional systems. Single qubit measurement and unitary processes and multipartite unitaries (where the unitary acts non-separably across two distant locations) acting on photons are discriminated with a confidence of $\geq97%$ in all cases.