Efficient and long-lived quantum memory with cold atoms inside a ring cavity

By Xiao-Hui Bao, Andreas Reingruber, P. Dietrich, Jun Rui, Alexander Dück, Thorsten Strassel, Li Li, Nai-Le Liu, Bo Zhao, Jian-Wei Pan. Nature Physics, 2012

191 citations recorded by the source corpus.

A quantum memory that combines high-efficiency and long lifetime is now demonstrated. Employing a collective excitation, or spin wave, in an ensemble of atoms in a trap improves memory lifetime, while incorporating the trap into an optical ring cavity simultaneously aids higher retrieval efficiency. Quantum memories are regarded as one of the fundamental building blocks of linear-optical quantum computation1 and long-distance quantum communication2. A long-standing goal to realize scalable quantum information processing is to build a long-lived and efficient quantum memory. There have been significant efforts distributed towards this goal. However, either efficient but short-lived3,4 or long-lived but inefficient quantum memories5,6,7 have been demonstrated so far. Here we report a high-performance quantum memory in which long lifetime and high retrieval efficiency meet for the first time. By placing a ring cavity around an atomic ensemble, employing a pair of clock states, creating a long-wavelength spin wave and arranging the set-up in the gravitational direction, we realize a quantum memory with an intrinsic spin wave to photon conversion efficiency of 73(2)% together with a storage lifetime of 3.2(1) ms. This realization provides an essential tool towards scalable linear-optical quantum information processing.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/8da9fd56d79d2d5d1c4c58f1804bda8d45485f02

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Quantum memories: emerging applications and recent advances (2015, methodology): “Optical cavities have also been used to demonstrate efficient coupling between atomic vapour memories and the cavity mode, with the cavity increasing the coupling strength [138, 139].”
Micius quantum experiments in space (2022, background): “As a milestone, the approach of utilizing cold atomic ensembles afforded an efficient quantum memory with a subsecond lifetime in 2016, with the two parameters fulfilling the requirement of long-distance quantum repeaters for the first time (Zhao et al., 2009; Bao et al., 2012; Yang et al., 2016).”