Unified simulation methods for quantum acoustic devices

TL;DR

This paper introduces unified simulation methods for quantum acoustic devices, enabling accurate modeling of superconducting qubits coupled with acoustic and microwave resonators, which improves understanding of mode hybridization and dissipation.

Contribution

The authors develop a single simulation approach and two predictive methods for hybrid quantum systems, addressing limitations of separate subsystem simulations in cQAD.

Findings

Successful simulation of a superconducting qubit with acoustic and microwave resonators

Methods for predicting frequencies, coupling rates, and energy-participation ratios

Framework for investigating dissipation channels and mode hybridization

Abstract

In circuit quantum acoustodynamics (cQAD), superconducting circuits are combined with acoustic resonators to create and control non-classical states of mechanical motion. Simulating these systems is challenging due to the extreme difference in scale between the microwave and mechanical wavelengths. All existing techniques simulate the electromagnetic and mechanical subsystems separately. However, this approach may not be adequate for all cQAD devices. Here, we demonstrate a single simulation of a superconducting qubit coupled to an acoustic and a microwave resonator and introduce two methods for using this simulation to predict the frequencies, coupling rates, and energy-participation ratios of the electromechanical modes of the hybrid system. We also discuss how these methods can be used to investigate important dissipation channels and quantify the nontrivial effects of mode hybridization in our device. Our methodology is flexible and can be extended to other acoustic resonators and quantum degrees of freedom, providing a valuable new tool for designing hybrid quantum systems.