Exceptional points in tunable superconducting resonators

Abstract

Exceptional points enable the fastest possible dissipative energy transfer between quantum systems and, hence, are potentially required in optimal cooling of qubits. The realization of exceptional points in superconducting circuits is particularly appealing because quantum circuits are key candidates for the emerging quantum computing. In the present work, the exceptional points are realized using a superconducting resonator with a tunable frequency and damping rate, provided by a superconducting quantum interference device and a quantum-circuit refrigerator, respectively.