Design and modeling of surface acoustic wave devices for quantum acoustic experiments

Microwave frequency surface acoustic wave (SAW) resonators can be integrated with superconducting qubits within the framework of circuit quantum acoustodynamics (cQAD). By engineering interactions between the qubit and a resonant SAW mode, cQAD techniques have been used to coherently manipulate and exchange information between the SAW and qubit. In addition to these coherent interactions, the lossy dynamics of the joint SAW-qubit open quantum system are also rich, as the hybrid system interacts with a bath of fluctuating two-level systems via both mechanical and electrical coupling. Additionally, the qubit can couple to lossy SAW modes that can dominate qubit decay. While numerical modeling methods for superconducting qubit based experiments are well developed, modeling the simultaneous electrical and mechanical interactions in cQAD remains challenging. Here we present numerical modeling and simulations of a hybrid system composed of a SAW resonator, transmon and coupling element, in which we model not only coherent coupling between these elements but also loss channels in the hybrid system. We discuss measurements to confirm the results of this modeling, as well as how they guide the design of future SAW-based cQAD experiments.