---
_id: '10058'
abstract:
- lang: eng
  text: 'Quantum information and computation has become a vast field paved with opportunities
    for researchers and investors. As large multinational companies and international
    funds are heavily investing in quantum technologies it is still a question which
    platform is best suited for the task of realizing a scalable quantum processor.
    In this work we investigate hole spins in Ge quantum wells. These hold great promise
    as they possess several favorable properties: a small effective mass, a strong
    spin-orbit coupling, long relaxation time and an inherent immunity to hyperfine
    noise. All these characteristics helped Ge hole spin qubits to evolve from a single
    qubit to a fully entangled four qubit processor in only 3 years. Here, we investigated
    a qubit approach leveraging the large out-of-plane g-factors of heavy hole states
    in Ge quantum dots. We found this qubit to be reproducibly operable at extremely
    low magnetic field and at large speeds while maintaining coherence. This was possible
    because large differences of g-factors in adjacent dots can be achieved in the
    out-of-plane direction. In the in-plane direction the small g-factors, on the
    other hand, can be altered very effectively by the confinement potentials. Here,
    we found that this can even lead to a sign change of the g-factors. The resulting
    g-factor difference alters the dynamics of the system drastically and produces
    effects typically attributed to a spin-orbit induced spin-flip term.  The investigations
    carried out in this thesis give further insights into the possibilities of holes
    in Ge and reveal new physical properties that need to be considered when designing
    future spin qubit experiments.'
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: The author gratefully acknowledges support by the Austrian Science
  Fund (FWF), grants No P30207, and the Nomis foundation.
alternative_title:
- ISTA Thesis
article_processing_charge: No
author:
- first_name: Daniel
  full_name: Jirovec, Daniel
  id: 4C473F58-F248-11E8-B48F-1D18A9856A87
  last_name: Jirovec
  orcid: 0000-0002-7197-4801
citation:
  ama: Jirovec D. Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional
    Ge hole gases. 2021. doi:<a href="https://doi.org/10.15479/at:ista:10058">10.15479/at:ista:10058</a>
  apa: Jirovec, D. (2021). <i>Singlet-Triplet qubits and spin-orbit interaction in
    2-dimensional Ge hole gases</i>. Institute of Science and Technology Austria.
    <a href="https://doi.org/10.15479/at:ista:10058">https://doi.org/10.15479/at:ista:10058</a>
  chicago: Jirovec, Daniel. “Singlet-Triplet Qubits and Spin-Orbit Interaction in
    2-Dimensional Ge Hole Gases.” Institute of Science and Technology Austria, 2021.
    <a href="https://doi.org/10.15479/at:ista:10058">https://doi.org/10.15479/at:ista:10058</a>.
  ieee: D. Jirovec, “Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional
    Ge hole gases,” Institute of Science and Technology Austria, 2021.
  ista: Jirovec D. 2021. Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional
    Ge hole gases. Institute of Science and Technology Austria.
  mla: Jirovec, Daniel. <i>Singlet-Triplet Qubits and Spin-Orbit Interaction in 2-Dimensional
    Ge Hole Gases</i>. Institute of Science and Technology Austria, 2021, doi:<a href="https://doi.org/10.15479/at:ista:10058">10.15479/at:ista:10058</a>.
  short: D. Jirovec, Singlet-Triplet Qubits and Spin-Orbit Interaction in 2-Dimensional
    Ge Hole Gases, Institute of Science and Technology Austria, 2021.
date_created: 2021-09-30T07:53:49Z
date_published: 2021-10-05T00:00:00Z
date_updated: 2023-09-08T11:41:08Z
day: '05'
ddc:
- '621'
- '539'
degree_awarded: PhD
department:
- _id: GradSch
- _id: GeKa
doi: 10.15479/at:ista:10058
file:
- access_level: closed
  checksum: ad6bcb24083ed7c02baaf1885c9ea3d5
  content_type: application/x-zip-compressed
  creator: djirovec
  date_created: 2021-09-30T14:29:14Z
  date_updated: 2022-12-20T23:30:07Z
  embargo_to: open_access
  file_id: '10061'
  file_name: PHD_Thesis_Jirovec_Source.zip
  file_size: 32397600
  relation: source_file
- access_level: open_access
  checksum: 5fbe08d4f66d1153e04c47971538fae8
  content_type: application/pdf
  creator: djirovec
  date_created: 2021-10-05T07:56:49Z
  date_updated: 2022-12-20T23:30:07Z
  embargo: 2022-10-06
  file_id: '10087'
  file_name: PHD_Thesis_pdfa2b_1.pdf
  file_size: 26910829
  relation: main_file
file_date_updated: 2022-12-20T23:30:07Z
has_accepted_license: '1'
keyword:
- qubits
- quantum computing
- holes
language:
- iso: eng
month: '10'
oa: 1
oa_version: Published Version
page: '151'
project:
- _id: 2641CE5E-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: P30207
  name: Hole spin orbit qubits in Ge quantum wells
publication_identifier:
  issn:
  - 2663-337X
publication_status: published
publisher: Institute of Science and Technology Austria
related_material:
  record:
  - id: '8831'
    relation: part_of_dissertation
    status: public
  - id: '10065'
    relation: part_of_dissertation
    status: public
  - id: '10066'
    relation: part_of_dissertation
    status: public
  - id: '8909'
    relation: part_of_dissertation
    status: public
  - id: '5816'
    relation: part_of_dissertation
    status: public
status: public
supervisor:
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
  orcid: 0000-0001-8342-202X
title: Singlet-Triplet qubits and spin-orbit interaction in 2-dimensional Ge hole
  gases
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: dissertation
user_id: c635000d-4b10-11ee-a964-aac5a93f6ac1
year: '2021'
...