A Hybrid Quantum Memory Enabled Network at Room Temperature

TL;DR

This paper demonstrates a hybrid quantum memory network operating at room temperature, integrating atomic-ensemble and all-optical loop memories for efficient quantum information processing and photon manipulation.

Contribution

It introduces the first hybrid quantum memory network that interconnects atomic and optical memories, enabling on-demand photon storage, conversion, and complex quantum state operations at room temperature.

Findings

Achieved a quantum cross-correlation of 22 between memories.

Demonstrated violation of the Cauchy-Schwarz inequality by 549 standard deviations.

Created and stored a fully operable heralded photon chain state.

Abstract

Quantum memory capable of storage and retrieval of flying photons on demand is crucial for developing quantum information technologies. However, the devices needed for long-distance links are quite different from those envisioned for local processing. Here, we present the first hybrid quantum memory enabled network by demonstrating the interconnection and simultaneous operation of two types of quantum memory: an atomic-ensemble-based memory and an all-optical loop memory. The former generates and stores single atomic excitations that can then be converted to single photons; and the latter maps incoming photons in and out on demand, at room-temperature and with a broad acceptance bandwidth. Interfacing these two types of quantum memories, we observe a well-preserved quantum cross-correlation, reaching a value of 22, and a violation of the Cauchy-Schwarz inequality up to 549 standard deviations. Furthermore, we demonstrate the creation and storage of a fully operable heralded photon chain state that can achieve memory-built-in combining, swapping, splitting, tuning and chopping single photons in a chain temporally. Such a quantum network allows atomic excitations to be generated, stored, and converted to broadband photons, which are then transferred to the next node, stored, and faithfully retrieved, all at high speed and in a programmable fashion.