Interfacing microwave qubits and optical photons via spin ensembles
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.
Cite
@article{arxiv.1501.05860,
title = {Interfacing microwave qubits and optical photons via spin ensembles},
author = {Susanne Blum and Christopher O'Brien and Nikolai Lauk and Pavel Bushev and Michael Fleischhauer and Giovanna Morigi},
journal= {arXiv preprint arXiv:1501.05860},
year = {2015}
}