Tuning coupling between superconducting resonators with collective qubits. (arXiv:1712.04357v1 [quant-ph])

By coupling multiple artificial atoms simultaneously to two superconducting
resonators, we construct a quantum switch that controls the resonator-resonator
coupling strength from zero to a large value proportional to the number of
qubits. This process is implemented by switching the qubits among different
\emph{subradiant states}, where the microwave photons decayed from different
qubits interfere destructively so that the coupling strength keeps stable
against environmental noise. Based on a two-step control scheme, the coupling
strength can be switched at the \emph{nanosecond} scale while the qubits are
maintained at the coherent optimal point. We also use the quantum switch to
connect multiple resonators with a programmable network topology, and
demonstrate its potential applications in quantum simulation and scalable
quantum information storage and processing.

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