Optical bistability via Josephson coupling energy in a superconducting quantum circuit

Abstract

A novel configuration is proposed to study optical bistability (OB) and optical multistability (OM) in a superconducting quantum circuit with a tunable V-type artificial molecule constructed by two superconducting Josephson charge qubits coupled with each other through a superconducting quantum interference device. We find that the ratio of the Josephson coupling energy to the capacitive coupling strength has a significant impact on creating optical bistability. The influence of other system parameters on bistable behavior of the artificial medium is then discussed. In particular, it is found that applying an incoherent pumping field can noticeably reduce the bistable threshold. We also realize a switch from OB to OM through proper tuning of detuning parameters. The controllability of OB and OM of this artificial molecule may be useful in building logic-gate devices for optical computing and quantum information processing and provide some new possibilities for solid-state quantum information science.