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arXiv · 1712.03668

Decoherence-protected memory for a single-photon qubit

M. Körber·O. Morin·S. Langenfeld·A. Neuzner·S. Ritter·G. Rempe
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Abstract

The long-lived, efficient storage and retrieval of a qubit encoded on a photon is an important ingredient for future quantum networks. Although systems with intrinsically long coherence times have been demonstrated, the combination with an efficient light-matter interface remains an outstanding challenge. In fact, the coherence times of memories for photonic qubits are currently limited to a few milliseconds. Here we report on a qubit memory based on a single atom coupled to a high-finesse optical resonator. By mapping and remapping the qubit between a basis used for light-matter interfacing and a basis which is less susceptible to decoherence, a coherence time exceeding 100 ms has been measured with a time-independant storage-and-retrieval efficiency of 22%. This demonstrates the first photonic qubit memory with a coherence time that exceeds the lower bound needed for teleporting qubits in a global quantum internet.

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M. Körber, O. Morin, S. Langenfeld, A. Neuzner, S. Ritter, G. Rempe. 2017-12-11. Decoherence-protected memory for a single-photon qubit. https://doi.org/10.1038/s41566-017-0050-y

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