Multimode interferometry for entangling atoms in quantum networks

TL;DR

This paper demonstrates a hybrid quantum system combining cavity-enhanced light-matter interfaces with integrated multimode interferometers to generate and verify entanglement between remote atoms via photonic qubits.

Contribution

It introduces a novel integrated multimode interferometer system that enables entanglement of remote atoms in a quantum network using deterministic photon sources.

Findings

Non-classical photon coincidences show preserved coherence after interference.

Integrated multimode circuits can mediate entanglement between remote quantum nodes.

High two-photon visibility confirms effective entanglement distribution.

Abstract

We bring together a cavity-enhanced light-matter interface with a multimode interferometer (MMI) integrated onto a photonic chip and demonstrate the potential of such hybrid systems to tailor distributed entanglement in a quantum network. The MMI is operated with pairs of narrowband photons produced a priori deterministically from a single 87Rb atom strongly coupled to a high-finesse optical cavity. Non-classical coincidences between photon detection events show no loss of coherence when interfering pairs of these photons through the MMI in comparison to the two-photon visibility directly measured using Hong-Ou-Mandel interference on a beam splitter. This demonstrates the ability of integrated multimode circuits to mediate the entanglement of remote stationary nodes in a quantum network interlinked by photonic qubits.