Fast Initialization Experiment of Superconducting Qubit Using SINIS*

We report an experiment of fast initialization of superconducting qubit using SINIS.
Active and unconditional initialization is required for NISQ, surface code and quantum computation.
By applying a bias voltage to the SINIS, photon assisted tunneling occurs, and the Q value of the resonator can be temporarily deteriorated. A qubit is coupled to the resonator, energy is transferred from the qubit to the resonator by applying two drive pulses which are an existing initialization scheme, and energy is efficiently emitted to the environment by natural relaxation of the resonator. Further, when initialization is not performed, that is, when a bias voltage is not applied to SINIS, the Q value of the resonator returns, so that the Q value does not affect readout and gate operation.
In this presentation, we report the experimental results and fabrication of the device.