Quantum Dot Circuit Quantum Electrodynamics

In the context of superconducting devices, circuit QED provides elegant solutions for qubit control, readout, and coupling.$^{\mathrm{1}}$ I will describe our efforts to develop hybrid ``super-semi'' quantum systems that combine some of the most promising elements of superconducting and long coherence time spin-based quantum computing technologies. In the charge sector, we electric-dipole couple semiconductor double quantum dots (DQDs) to superconducting cavities and demonstrate dispersive readout of DQD charge stability diagrams.$^{\mathrm{2}}$ In the two-electron regime, the Pauli exclusion principle enables dispersive readout of singlet and triplet spin states.$^{\mathrm{3}}$ Overlapping gate electrodes fabricated on Si heterostructures have greatly improved charge coherence, ushering in a new era of strong-coupling quantum dot cQED.$^{\mathrm{4}}$ By placing a Si DQD in a large magnetic field gradient, we have recently achieved strong coupling between a single spin and a single microwave photon.$^{\mathrm{5}}$ These developments in quantum dot cQED, combined with recent demonstrations of high-fidelity two-qubit gates in Si,$^{\mathrm{\thinspace }}$firmly anchor Si as a leading material system in the worldwide race to develop a scalable quantum computer.$^{\mathrm{6}}$\\ \\ $[1.]$ X. Gu \textit{et al}., Phys. Rep. \textbf{718}, 1 (2017).\newline $[2.]$ J. Stehlik \textit{et al.}, Phys. Rev. Appl. \textbf{4}, 014018 (2015).\newline $[3.]$ K. D. Petersson \textit{et al.}, Nature \textbf{490}, 380 (2012).\newline $[4.]$ X. Mi \textit{et al.}, Science \textbf{355}, 156 (2017).\newline $[5.]$ X. Mi \textit{et al.}, Nature (submitted).\newline $[6.]$ D. M. Zajac \textit{et al.}, Science aao5965 (2017).