Title: Hybrid quantum phononics with superconducting qubits*

Abstract: Superconducting qubits, and the experimental architecture of circuit quantum
electrodynamics (cQED), have emerged as not only a promising platform for quantum
computation but also for investigating fundamental and applied aspects of
synthetic/hybrid quantum systems composed of qubits coupled to other quantum systems
or degrees of freedom. In particular, the ability to leverage the properties of
superconducting qubits to investigate and manipulate phononic degrees of freedom opens
the door to exploring new regimes of circuit quantum optics using high-frequency sound.
Due to the intrinsically strong nonlinearity provided by the qubit, these types of hybrid
“quantum acoustic” systems have the potential to access a broad class of quantum states
of motion beyond what is achievable with effectively linear optomechanical or
electromechanical interactions.
In this talk I will describe some of our recent experimental results investigating the
fundamental physics of hybrid systems based on superconducting qubits coupled to
piezoelectric surface and bulk acoustic wave devices and how these systems can be used
to develop next-generation technologies for quantum sensing, computation, and
communication. As I will describe, these engineered systems, in which quantum
information stored in the qubit can be controllably coupled to the microscopic surface
and bulk phonon modes of a piezoelectric crystal, are an ideal platform for investigating
the exotic behavior of synthetic open quantum systems and phononic interference in the
quantum regime. Additionally, I will describe how these devices pave the way to exciting
new technologies ranging from quantum-limited surface sensing to phonon-based
bosonic quantum memories.

*This work was supported by the National Science Foundation via Grant No. ECCS-2142846 (CAREER)