A Scalable Room-Temperature Quantum Processing Network

Norman Y. Yao, Liang Jiang, Alexey Vyacheslavovich Gorshkov +4 more

Bertus Jordaan, Reihaneh Shahrokhshahi, Mehdi Namazi +2 more

Johannes Borregaard, Michael Zugenmaier, J. M. Petersen +5 more

Quantum interfaces between photons and atomic ensembles have emerged as powerful tools for quantum technologies. Efficient storage and retrieval of single photons requires long-lived collective atomic states, which is typically achieved with immobilized atoms. Thermal atomic vapours, which present a simple and scalable resource, have only been used for continuous variable processing or for discrete variable processing on short timescales where atomic motion is negligible. Here we develop a theory based on motional averaging to enable room temperature discrete variable quantum memories and coherent single-photon sources. We demonstrate the feasibility of this approach to scalable quantum memories with a proof-of-principle experiment with room temperature atoms contained in microcells with spin-protecting coating, placed inside an optical cavity. The experimental conditions correspond to a few photons per pulse and a long coherence time of the forward scattered photons is demonstrated, which is the essential feature of the motional averaging.

Ruoxi Wang

Quantum memory provides a platform for building quantum networks in quantum information processing. Applications of said networks include quantum gates for quantum computing and quantum repeaters for long distance quantum key distribution. An optical quantum memory can be realized by a cold atom system combined with electromagnetically induced transparency (EIT). However, room temperature quantum memory via vapor cells benefit from its easy operation without the need for laser cooling and trapping, promoting the scalability. In this work, we studied and tested EIT in a Rubidium vapor cell at room temperature, by storing and retrieving a classical light source using probe and control lasers. We also constructed a portable quantum memory system and realized the storage of light at the single-photon level at room temperature. For a future perspective, we designed the quantum memory system with cavities, wishing to breakthrough in storage efficiency. | 37 pages

H. G. J. Eenink, Luca Petit, Menno Veldhorst

Chao-Ni Zhang, Xiao-Ling Pang, Jian-Peng Dou +3 more

Photons with high generation rate is one of the essential resources for quantum communication, quantum computing and quantum metrology. Due to the naturally memory-built-in feature, the memory-based photon source is a promising route towards large-scale quantum information processing. However, such photon sources are mostly implemented in extremely low-temperature ensembles or isolated systems, limiting its physical scalability. Here we realize a single-photon source based on a far off-resonance Duan-Lukin-Cirac-Zoller quantum memory at broadband and room-temperature regime. By harnessing high-speed feedback control and repeat-until-success write process, the photon generation rate obtains considerable enhancement up to tenfold. Such a memory-enhanced single-photon source, based on the broadband room-temperature quantum memory, suggests a promising way for establishing large-scale quantum memory-enabled network at ambient condition.