Unambiguous discrimination of general quantum operations

TL;DR

This paper reports the first experimental demonstration of optimal unambiguous discrimination of general quantum operations, including non-unitary and displacement operators, advancing quantum information processing and sensing capabilities.

Contribution

It provides the first experimental realization of unambiguous discrimination of general quantum operations, including non-unitary cases, in high-dimensional quantum systems.

Findings

Successfully discriminated up to 6 displacement operators.

Demonstrated discrimination of non-unitary quantum operations.

Showcased practical tools for quantum information and sensing applications.

Abstract

The discrimination of quantum operations has long been an intriguing challenge, with theoretical research significantly advancing our understanding of the quantum features in discriminating quantum objects. This challenge is closely related to the discrimination of quantum states, and proof-of-principle demonstrations of the latter have already been realized using optical photons. However, the experimental demonstration of discriminating general quantum operations, including both unitary and non-unitary operations, has remained elusive. In general quantum systems, especially those with high dimensions, the preparation of arbitrary quantum states and the implementation of arbitrary quantum operations and generalized measurements are non-trivial tasks. Here, for the first time, we experimentally demonstrate the optimal unambiguous discrimination of up to 6 displacement operators and the unambiguous discrimination of non-unitary quantum operations. Our results demonstrate powerful tools for experimental research in quantum information processing and are expected to stimulate a wide range of valuable applications in the field of quantum sensing.