Topologically robust transport of entangled photons in a 2D photonic system

TL;DR

This paper demonstrates that topologically protected edge states in a 2D photonic system enable robust transport of entangled photons, preserving their temporal correlations even in the presence of disorder, which is promising for quantum communication.

Contribution

The study introduces a theoretical model showing topologically robust transport of entangled photons in a 2D photonic system, highlighting the preservation of correlations via edge states.

Findings

Edge states preserve entangled photon correlations.

Bulk transport is susceptible to disorder and causes localization.

Disorder leads to photon bunching or anti-bunching effects.

Abstract

We theoretically study the transport of time-bin entangled photon pairs in a two-dimensional topological photonic system of coupled ring resonators. This system implements the integer quantum Hall model using a synthetic gauge field and exhibits topologically robust edge states. We show that the transport through edge states preserves temporal correlations of entangled photons whereas bulk transport does not preserve these correlations and can lead to significant unwanted temporal bunching or anti-bunching of photons. We study the effect of disorder on the quantum transport properties; while the edge transport remains robust, bulk transport is very susceptible, and in the limit of strong disorder, bulk states become localized. We show that this localization is manifested as an enhanced bunching/anti-bunching of photons. This topologically robust transport of correlations through edge states could enable robust on-chip quantum communication channels and delay lines for information encoded in temporal correlations of photons.