AQP Seminar: Fast qubit reset with a quantum circuit refrigerator

Abstract: 

Superconducting qubits have emerged as powerful building blocks for a potential quantum computer. However, controlling superconducting qubits remains a challenge, particularly resetting the qubit into the ground state. Although a qubit naturally relaxes to its lowest-energy state, this process can take a significant amount of time and eventually inhibit fast computing.

A promising solution is the quantum circuit refrigerator (QCR), an electronic microcooler based on single electron tunneling in a pair of normal metal-insulator-superconductor (NIS) junctions. It can reduce the electron temperature locally below the phonon bath temperature and has previously been applied to superconducting transmission line resonators [1]. We investigate an active, controlled reset of a transmon qubit using a QCR, its associated effects and optimization in this structure.

[1] Tan, K. Y. et al. Quantum-circuit refrigerator. Nat. Comm. 8, 15189 (2017).