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arXiv · 1501.05860

Interfacing microwave qubits and optical photons via spin ensembles

Susanne Blum·Christopher O'Brien·Nikolai Lauk·Pavel Bushev·Michael Fleischhauer·Giovanna Morigi
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Abstract

A protocol is discussed which allows one to realize a transducer for single photons between the optical and the microwave frequency range. The transducer is a spin ensemble, where the individual emitters possess both an optical and a magnetic-dipole transition. Reversible frequency conversion is realized by combining optical photon storage, by means of EIT, with the controlled switching of the coupling between the magnetic-dipole transition and a superconducting qubit, which is realized by means of a microwave cavity. The efficiency is quantified by the global fidelity for transferring coherently a qubit excitation between a single optical photon and the superconducting qubit. We test various strategies and show that the total efficiency is essentially limited by the optical quantum memory: It can exceed 80% for ensembles of NV centers and approaches 99% for cold atomic ensembles, assuming state-of-the-art experimental parameters. This protocol allows one to bridge the gap between the optical and the microwave regime so to efficiently combine superconducting and optical components in quantum networks.

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Susanne Blum, Christopher O'Brien, Nikolai Lauk, Pavel Bushev, Michael Fleischhauer, Giovanna Morigi. 2015-01-23. Interfacing microwave qubits and optical photons via spin ensembles. https://doi.org/10.1103/physreva.91.033834

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