Quantum acoustics with superconducting circuits
Doctoral thesis, 2020

The past 20 years has seen rapid developments in circuit quantum electrodynamics, where superconducting qubits and resonators are used to control and study quantum light-matter interaction at a fundamental level. The development of this field is strongly influenced by quantum information science and the prospect of realizing quantum computation, but also opens up opportunities for combinations of different physical systems and research areas. Superconducting circuits in the microwave domain offer a versatile platform for interfacing with other quantum systems thanks to strong nonlinearities and zero-point fluctuations, as well as flexibility in design and fabrication. Hybrid quantum systems based on circuit quantum electrodynamics could enable novel functionalities by exploiting the strengths of the individual components.

This thesis covers experiments coupling superconducting circuits to surface acoustic waves (SAWs), mechanical waves propagating along the surface of a solid. Strong coupling can be engineered using the piezoelectric properties of GaAs substrates, and our experiments exploit this to investigate phenomena in quantum field-matter interaction. A key property of surface acoustic waves is the slow propagation speed, typically five orders of magnitude slower than light in vacuum, and the associated short wavelength. This enables the giant atom regime where the artificial atom in the form of a superconducting circuit is large compared to the wavelength of interacting SAW radiation, a condition which is difficult to realize in other systems. Experiments described in this thesis use these properties to demonstrate electromagnetically induced transparency for a mechanical mode, as well as non-Markovian interactions between an artificial giant atom and the SAW field.

When the SAW field is confined to a resonant cavity, the short wavelength allows multimode spectra suitable for interacting with a frequency comb. We use a multimode SAW resonator to characterize the ensemble of microscopic two-level system defects with a two-tone spectroscopy approach. Finally, we introduce a hybrid superconducting-SAW resonator with applications in quantum information processing in mind. Experiments with this device demonstrate entanglement of SAW modes, and show promising results on the way to engineer cluster states for quantum computation in continuous variables.

cluster states

two-mode squeezing

SAW

giant atoms

two-level systems

hybrid quantum systems

quantum acoustics

circuit QED

superconducting qubits

surface acoustic wave

Kollektorn, Kemivägen 9
Opponent: Prof. Yasunobu Nakamura, Research Center for Advanced Science and Technology, University of Tokyo, Japan

Author

Gustav Andersson

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Technology

Non-exponential decay of a giant artificial atom

Nature Physics,; Vol. 15(2019)p. 1123-1127

Journal article

Electromagnetically Induced Acoustic Transparency with a Superconducting Circuit

Physical Review Letters,; Vol. 124(2020)

Journal article

Andersson, G, Oliveira Bilobran, A, Scigliuzzo, M, de Lima, M. M, Cole, J. H, Delsing, P. Acoustic spectral hole-burning in a two-level sytem ensemble

Andersson, G, Jolin, S. W, Scigliuzzo, M, Borgani, R, Tholén, M. O, Haviland, D. B, Delsing, P. Squeezing and correlations of mulitple modes in a parametric acoustic cavity

The past 20 years has seen rapid developments in circuit quantum electrodynamics, where superconducting qubits and resonators are used to control and study quantum light-matter interaction at a fundamental level. The development of this field is strongly influenced by quantum information science and the prospect of realizing quantum computation, but also opens up opportunities for combinations of different physical systems and research areas. Superconducting circuits in the microwave domain offer a versatile platform for interfacing with other quantum systems thanks to strong nonlinearities and zero-point fluctuations, as well as flexibility in design and fabrication. Hybrid quantum systems based on circuit quantum electrodynamics could enable novel functionalities by exploiting the strengths of the individual components.

This thesis covers experiments coupling superconducting circuits to surface acoustic waves (SAWs), mechanical waves propagating along the surface of a solid. Strong coupling can be engineered using the piezoelectric properties of GaAs substrates, and our experiments exploit this to investigate phenomena in quantum field-matter interaction. A key property of surface acoustic waves is the slow propagation speed, typically five orders of magnitude slower than light in vacuum, and the associated short wavelength. This enables the giant atom regime where the artificial atom in the form of a superconducting circuit is large compared to the wavelength of interacting SAW radiation, a condition which is difficult to realize in other systems. Experiments described in this thesis use these properties to demonstrate electromagnetically induced transparency for a mechanical mode, as well as non-Markovian interactions between an artificial giant atom and the SAW field.

When the SAW field is confined to a resonant cavity, the short wavelength allows multimode spectra suitable for interacting with a frequency comb. We use a multimode SAW resonator to characterize the ensemble of microscopic two-level system defects with a two-tone spectroscopy approach. Finally, we introduce a hybrid superconducting-SAW resonator with applications in quantum information processing in mind. Experiments with this device demonstrate entanglement of SAW modes, and show promising results on the way to engineer cluster states for quantum computation in continuous variables.

Areas of Advance

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Subject Categories

Physical Sciences

Infrastructure

Nanofabrication Laboratory

ISBN

978-91-7905-351-2

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4818

Publisher

Chalmers University of Technology

Kollektorn, Kemivägen 9

Online

Opponent: Prof. Yasunobu Nakamura, Research Center for Advanced Science and Technology, University of Tokyo, Japan

More information

Latest update

8/12/2020