Tutorial 5: Superconducting Quantum Hybrid Systems

Over the last ten years superconducting researchers have learned how to couple qubits through microwave resonators over chip-scale distances via “circuit-QED”, the microwave analog of cavity QED in quantum optics. This has enabled the design of practical multi-qubit architectures. While semiconductor-based spin qubits have the advantage of electrically controlled, high on-off ratio Heisenberg exchange for qubit coupling, the close physical proximity required leads to very dense qubit arrays with no possibility of long range coupling. A natural compromise is a hybrid system that couples the spin of electrons in quantum dots to one another via microwave photons in a cavity analogous to circuit-QED. This tutorial will cover the fundamentals of the semiconductor and superconductor components in hybrid systems, the challenges of each and the promise of a truly modular spin qubit architecture.