Hong-Ou-Mandel interference of polarization qubits stored in independent room-temperature quantum memories

TL;DR

This paper demonstrates Hong-Ou-Mandel interference between polarization qubits stored in independent room-temperature quantum memories, showing progress towards scalable quantum networks.

Contribution

It presents the first experimental realization of HOM interference with polarization qubits stored in independent room-temperature quantum memories.

Findings

Achieved a HOM visibility of 43% with quantum memories.

Improved memory parameters and interference visibility over time.

Set a foundation for large-scale memory-assisted quantum networks.

Abstract

Quantum repeater networks require independent quantum memories capable of storing and retrieving indistinguishable photons to perform high-repetition entanglement swapping operations. The ability to perform these coherent operations at room temperature is of prime importance to the realization of scalable quantum networks. We perform Hong-Ou-Mandel (HOM) interference between photonic polarization qubits stored and retrieved from two sets of independent room-temperature quantum memories. We show a steady improvement in memory parameters and visibilities, culminating in a high quantum memory HOM visibility of 43%, compared to the 48% no-memory limit of our set-up. These results lay the groundwork for future applications using large-scale memory-assisted quantum networks.