Detecting Optical Channel Non-Reciprocity with Non-Local Quantum Geometric Phase

TL;DR

This paper demonstrates that non-reciprocal optical devices induce a measurable, non-local geometric phase detectable through entangled photons, offering a robust method for identifying non-reciprocity in quantum communication channels.

Contribution

It introduces a novel approach to detect optical non-reciprocity using non-local quantum geometric phases with entangled photons.

Findings

Non-reciprocal devices cause measurable geometric phases.

Entangled photons reveal non-local phase effects.

The method is robust against malicious interference.

Abstract

Non-reciprocal devices are of increasing interest in quantum information technologies. This paper examines whether the presence of a non-reciprocal device in an optical channel is detectable by the communicating parties. We find that a non-reciprocal device such as a Faraday Rotator results in a measurable geometric phase for the light propagating through the channel and that, when using entangled photon pairs, the resulting phase is non-local and robust against malicious manipulation.