@article {2149, title = {Input-output theory for spin-photon coupling in Si double quantum dots}, journal = {Physical Review B}, volume = {96}, year = {2017}, month = {2017/12/22}, pages = {235434}, 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.

}, doi = {10.1103/PhysRevB.96.235434}, url = {https://link.aps.org/doi/10.1103/PhysRevB.96.235434}, author = {Benito, M. and Mi, X. and J. M. Taylor and Petta, J. R. and Burkard, Guido} } @article {2152, title = {Threshold Dynamics of a Semiconductor Single Atom Maser}, journal = {Physical Review Letters}, volume = {119}, year = {2017}, month = {2017/08/31}, pages = {097702}, abstract = {

We demonstrate a single atom maser consisting of a semiconductor double quantum dot (DQD) that is embedded in a high-quality-factor microwave cavity. A finite bias drives the DQD out of equilibrium, resulting in sequential single electron tunneling and masing. We develop a dynamic tuning protocol that allows us to controllably increase the time-averaged repumping rate of the DQD at a fixed level detuning, and quantitatively study the transition through the masing threshold. We further examine the crossover from incoherent to coherent emission by measuring the photon statistics across the masing transition. The observed threshold behavior is in agreement with an existing single atom maser theory when small corrections from lead emission are taken into account.

}, doi = {10.1103/PhysRevLett.119.097702}, url = {https://link.aps.org/doi/10.1103/PhysRevLett.119.097702}, author = {Liu, Y.-Y. and Stehlik, J. and Eichler, C. and Mi, X. and Hartke, T. R. and Michael Gullans and J. M. Taylor and Petta, J. R.} }