Quantum acoustics with lithium niobate nanostructures

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Phononic crystals are today the most sophisticated technology for manipulating acoustic waves on the surface of a chip. As such, ordinarily these devices can be described by the classical physics of elasticity; accessing a regime where their behavior is manifestly quantum mechanical has so far remained elusive. One way of reaching this regime would be to use a superconducting qubit to monitor and control the acoustics. Such `quantum acoustic' devices would have wide-ranging applications to quantum transduction, sensing, and information processing. In this thesis I present a collection of works that lay the groundwork for realizing this vision. First I introduce a technique for calculating coupling strengths between superconducting circuits (which include, but are not restricted to, transmon qubits) and arbitrary piezoelectric nanostructures. I then present the first demonstration of direct, resonant coupling between a superconducting circuit and a phononic-crystal-defect resonator (PCDR). This required developing a fabrication process that combines superconducting microwave circuits and suspended lithium niobate nanostructures in a fully integrated, on-chip platform. I then present results from a later generation of devices, including the demonstration of a transmon qubit and an array of PCDRs in the strong coupling regime. Finally, using these same devices I show we can generate a strong dispersive interaction that results in phonon-number-dependent splitting of the qubit spectroscopic line. This constitutes the first observation of the quantized energy levels of a nanomechanical oscillator, taking us back to the original scientific motivation of directly observing the quantum mechanical nature of a (confined) acoustic wave. Needless to say, such dispersive physics also has applications in quantum sensing and information processing. I conclude with a discussion on future experiments along that direction, including quantum nondemolition measurements of single phonons and generation of coherent state superpositions (a.k.a. cat states) of mechanical motion.


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 2019; ©2019
Publication date 2019; 2019
Issuance monographic
Language English


Author Arrangoiz Arriola, Patricio
Degree supervisor Safavi-Naeini, Amir H
Thesis advisor Safavi-Naeini, Amir H
Thesis advisor Fejer, Martin M. (Martin Michael)
Thesis advisor Hayden, Patrick, 1965-
Degree committee member Fejer, Martin M. (Martin Michael)
Degree committee member Hayden, Patrick, 1965-
Associated with Stanford University, Department of Applied Physics.


Genre Theses
Genre Text

Bibliographic information

Statement of responsibility Patricio Arrangoiz Arriola.
Note Submitted to the Department of Applied Physics.
Thesis Thesis Ph.D. Stanford University 2019.
Location electronic resource

Access conditions

© 2019 by Patricio Arrangoiz Arriola
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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