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Input-output theory for spin-photon coupling in Si double quantum dots

Research paper by Mónica Benito, X. Mi, J. M. Taylor, J. R. Petta, Guido Burkard

Indexed on: 06 Oct '17Published on: 06 Oct '17Published in: arXiv - Physics - Mesoscopic Systems and Quantum Hall Effect



Abstract

The interaction of qubits via microwave frequency photons enables long-distance qubit-qubit coupling and facilitates the realization of a large-scale quantum processor. However, qubits based on electron spins in semiconductor quantum dots have proven challenging to couple to microwave photons. In this theoretical work we show that a sizable coupling for a single electron spin is possible via spin-charge hybridization using a magnetic field gradient in a silicon double quantum dot. Based on parameters already shown in recent experiments, we predict optimal working points to achieve a coherent spin-photon coupling, an essential ingredient for the generation of long-range entanglement. Furthermore, we employ input-output theory to identify observable signatures of spin-photon coupling in the cavity output field, which may provide guidance to the experimental search for strong coupling in such spin-photon systems and opens the way to cavity-based readout of the spin qubit.