Probe absorption characteristics and a tunable susceptibility switch of a superconducting flux qubit coupled to two mechanical resonators

Abstract

A scheme is proposed for exploring the absorption spectrum and the susceptibility of a loop-coupled hybrid system in which two mechanical resonators are coupled to a superconducting flux qubit. Theoretical analysis has shown that the transparency based on mechanically induced coherent population oscillation (MICPO) can be tuned by the Rabi frequency and the decay rate of the mechanical resonator. We put forward a new and precise scheme to measure the frequency of the mechanical resonator. Moreover, a method to design the nonlinear susceptibility switches is also provided. Simultaneously, the coupling strength between two mechanical resonators can be detected from the distance of two peaks in the probe spectrum. The study is of great significance to the fields of precision measurement and quantum information processing.