Hybrid systems based on electrons floating on superfluid helium

Piezoelectric surface acoustic waves (SAWs) are powerful for investigating and controlling elementary and collective excitations in condensed matter and quantum information science systems. In this talk I will describe our experiments on hybrid/synthetic quantum systems comprised of high-frequency SAW devices coupled to 1) electrons floating above the surface of superfluid helium and 2) superconducting qubit systems. Our experiments coupling electrons on helium to an evanescent piezoelectric SAW have allowed us to demonstrate precision acoustoelectric control of this unique trapped electron system for the first time. I will also discuss how these results open the door to an entirely new class of SAW-based experiments with electrons on helium in which the SAW wavelength can be made commensurate with the inter-electron distance. Additionally I will describe our recent experiments coupling GHz-frequency SAW resonators to superconducting qubits. In particular, I will describe a novel "quantum acoustic" architecture based on a purely capacitive coupling between a superconducting transmon qubit and a SAW resonator housed in a three-dimensional microwave cavity, which is able to achieve strong coupling (g ≅ 10 MHz) between the qubit excitations and SAW piezo-phonons.