Quantum control and characterization of phononic crystal cavities

Placeholder Show Content

Abstract/Contents

Abstract
The nonclassical behavior of mechanical objects is of both fundamental interest and potential technological utility. Mechanical resonators can be combined with superconducting microwave circuits to realize quantum technologies, acting as memories for computation and on-chip delay lines, with small footprints and large achievable coupling rates. The nonlinearity of the circuit enables quantum control of the mechanical mode, as well as nondemolition readout of the prepared mechanical states. This hybrid platform has seen great progress in recent years as both a flourishing technological avenue and as a platform to explore quantum behavior of mechanical motion. In this work, we describe a series of experiments which explore the versatile uses of a quantum acoustics platform built from piezoelectric nanomechanical resonators. First, we describe the design and experimental realization of a Purcell filter composed of lithium niobate Lamb-wave resonators. Next, we combine a superconducting transmon qubit with two phononic crystal resonators, also made of lithium niobate. We demonstrate full quantum control of the mechanical modes and perform quantum state tomography to extract the density matrices of the prepared states. In this effort, we also prepare and characterize a mechanical Bell-state between the two resonators, demonstrating a small-scale quantum acoustic processor. Last, using the same device, we use the qubit to perform phonon number-resolved detection of dissipation and dephasing of coherent states in the mechanical oscillator. We develop a model showing that the dissipation signatures are consistent with emission into a small ensemble of long-lived two-level system defects, thus elucidating the need for further refinement of fabrication techniques. Altogether, this dissertation represents an exploration of a wide range of different applications for a hybrid quantum acoustic platform.

Description

Type of resource text
Form electronic resource; remote; computer; online resource
Extent 1 online resource.
Place California
Place [Stanford, California]
Publisher [Stanford University]
Copyright date 2023; ©2023
Publication date 2023; 2023
Issuance monographic
Language English

Creators/Contributors

Author Cleland, Agnetta
Degree supervisor Safavi-Naeini, Amir H
Thesis advisor Safavi-Naeini, Amir H
Thesis advisor Hogan, Jason
Thesis advisor Schuster, David (David Isaac)
Degree committee member Hogan, Jason
Degree committee member Schuster, David (David Isaac)
Associated with Stanford University, School of Humanities and Sciences
Associated with Stanford University, Department of Applied Physics

Subjects

Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Agnetta Y. Cleland.
Note Submitted to the Department of Applied Physics.
Thesis Thesis Ph.D. Stanford University 2023.
Location https://purl.stanford.edu/kx366nm3915

Access conditions

Copyright
© 2023 by Agnetta Cleland
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

Also listed in

Loading usage metrics...