Quartz mechanical resonators for circuit quantum acoustics

Abstract

Quantum control of phonons is achieved by coupling superconducting qubits to mechanical oscillators, promising a compact hardware platform for quantum information processing.  However, these hybrid systems suffer short coherence times due to spontaneous qubit emission into lossy phononic modes. In my thesis defense, I will describe how crystalline quartz can be used to suppress loss mechanisms in hybrid circuit quantum acoustic devices by over an order of magnitude. This will include demonstrations of crystallographic orientation optimization and engineering of the acoustic mode spectrum. Additionally, I will present a new flip-chip architecture for hybrid devices, the `acoustic trampoline’.