Electron spins hold great promise for quantum computation due to their long coherence times. An approach to realize interactions between distant spin-qubits is to use photons as carriers of quantum information. We demonstrate strong coupling between single microwave photons in a NbTiN high impedance cavity and a three-electron spin-qubit in a GaAs triple quantum dot. We resolve the vacuum Rabi mode splitting with a coupling strength of g/2π≃31 MHz and a qubit decoherence of γ2/2π≃20 MHz. We can tune the decoherence electrostatically and obtain a minimal γ2/2π≃10 MHz for g/2π≃23 MHz. The dependence of the qubit-photon coupling strength on the tunable electric dipole moment of the qubit is measured directly using the ac Stark effect. Our demonstration of strong spin-photon interaction is an important step towards coherent long-distance coupling of spin-qubits.
@article{arxiv.1711.01932,
title = {Coherent spin-qubit photon coupling},
author = {A. J. Landig and J. V. Koski and P. Scarlino and U. C. Mendes and A. Blais and C. Reichl and W. Wegscheider and A. Wallraff and K. Ensslin and T. Ihn},
journal= {arXiv preprint arXiv:1711.01932},
year = {2018}
}