Controllable microwave three-wave mixing via a single three-level superconducting quantum circuit

TL;DR

This paper demonstrates controllable second-order nonlinear microwave processes in a superconducting three-level circuit by breaking inversion symmetry, enabling frequency conversion and harmonic generation in the microwave regime.

Contribution

It introduces a method to achieve second-order nonlinear processes in superconducting circuits by breaking inversion symmetry with magnetic flux.

Findings

Frequency tunability up to 17 GHz for sum-frequency generation.

Difference-frequency generation around 42 GHz or 26 GHz.

Feasible within current superconducting circuit experimental parameters.

Abstract

Three-wave mixing in second-order nonlinear optical processes cannot occur in atomic systems due to the electric-dipole selection rules. In contrast, we demonstrate that second-order nonlinear processes can occur in a superconducting quantum circuit (i.e., a superconducting artificial atom) when the inversion symmetry of the potential energy is broken by simply changing the applied magnetic flux. In particular, we show that difference- and sum-frequencies (and second harmonics) can be generated in the microwave regime in a controllable manner by using a single three-level superconducting flux quantum circuit (SFQC). For our proposed parameters, the frequency tunability of this circuit can be achieved in the range of about 17 GHz for the sum-frequency generation, and around 42 GHz (or 26 GHz) for the difference-frequency generation. Our proposal provides a simple method to generate second-order nonlinear processes within current experimental parameters of SFQCs.