Two-resonator circuit QED: A superconducting quantum switch

Understand

We introduce a systematic formalism for two-resonator circuit QED, where two on-chip microwave resonators are simultaneously coupled to one superconducting qubit.

• Within this framework, we demonstrate that the qubit can function as a quantum switch between the two resonators, which are assumed to be originally independent.
• In this three-circuit network, the qubit mediates a geometric second-order circuit interaction between the otherwise decoupled resonators.
• In the dispersive regime, it also gives rise to a dynamic second-order perturbative interaction.