Quickly Tunable Electromagnetic Environment for Superconducting Quantum Circuits*

In the qubits operation it is of utmost importance to be able to quickly remove any unwanted excitations on demand for fast and accurate initialization. We recently introduced a device referred to as a quantum-circuit refrigerator (QCR) [1]. It is a stand-alone component that can readily be integrated into superconducting quantum electric devices, with negligible perturbation to the device operation. In our experiments, we demonstrate the ability to tune the dissipation of a superconducting resonator by orders of magnitude by the convenient application of a bias voltage on the QCR. The switching time of the tunable dissipation can be as low as a few nanoseconds. We also observe a tunable Lamb shift owing to the dissipation induced by the QCR.
1 K. Y. Tan et al., Nat. Commun. 8, 15189 (2017)