Storing single photons emitted by a quantum memory on a highly excited Rydberg state

TL;DR

This paper demonstrates storing and retrieving a paired single photon in a Rydberg atomic ensemble, maintaining nonclassical correlations, advancing the development of deterministic photon-photon interactions for quantum information processing.

Contribution

It presents the first demonstration of storing a paired single photon emitted by a quantum memory in a Rydberg medium, preserving nonclassical correlations after retrieval.

Findings

Successful storage and retrieval of paired single photons in a Rydberg ensemble.

Nonclassical correlations between photons persist after retrieval.

Advancement towards deterministic photon-photon interactions in quantum networks.

Abstract

Strong interaction between two single photons is a long standing and important goal in quantum photonics. This would enable a new regime of nonlinear optics and unlock several applications in quantum information science, including photonic quantum gates and deterministic Bell-state measurements. In the context of quantum networks, it would be important to achieve interactions between single photons from independent photon pairs storable in quantum memories. So far, most experiments showing nonlinearities at the single-photon level have used weak classical input light. Here, we demonstrate the storage and retrieval of a paired single photon emitted by an ensemble quantum memory in a strongly nonlinear medium based on highly excited Rydberg atoms. We show that nonclassical correlations between the two photons persist after retrieval from the Rydberg ensemble. Our result is an important step towards deterministic photon-photon interactions, and may enable deterministic Bell-state measurements with multimode quantum memories.