---
_id: '9928'
abstract:
- lang: eng
  text: There are two elementary superconducting qubit types that derive directly
    from the quantum harmonic oscillator. In one, the inductor is replaced by a nonlinear
    Josephson junction to realize the widely used charge qubits with a compact phase
    variable and a discrete charge wave function. In the other, the junction is added
    in parallel, which gives rise to an extended phase variable, continuous wave functions,
    and a rich energy-level structure due to the loop topology. While the corresponding
    rf superconducting quantum interference device Hamiltonian was introduced as a
    quadratic quasi-one-dimensional potential approximation to describe the fluxonium
    qubit implemented with long Josephson-junction arrays, in this work we implement
    it directly using a linear superinductor formed by a single uninterrupted aluminum
    wire. We present a large variety of qubits, all stemming from the same circuit
    but with drastically different characteristic energy scales. This includes flux
    and fluxonium qubits but also the recently introduced quasicharge qubit with strongly
    enhanced zero-point phase fluctuations and a heavily suppressed flux dispersion.
    The use of a geometric inductor results in high reproducibility of the inductive
    energy as guaranteed by top-down lithography—a key ingredient for intrinsically
    protected superconducting qubits.
acknowledged_ssus:
- _id: NanoFab
- _id: M-Shop
acknowledgement: We thank W. Hughes for analytic and numerical modeling during the
  early stages of this work, J. Koch for discussions and support with the scqubits
  package, R. Sett, P. Zielinski, and L. Drmic for software development, and G. Katsaros
  for equipment support, as well as the MIBA workshop and the Institute of Science
  and Technology Austria nanofabrication facility. We thank I. Pop, S. Deleglise,
  and E. Flurin for discussions. This work was supported by a NOMIS Foundation research
  grant, the Austrian Science Fund (FWF) through BeyondC (F7105), and IST Austria.
  M.P. is the recipient of a Pöttinger scholarship at IST Austria. E.R. is the recipient
  of a DOC fellowship of the Austrian Academy of Sciences at IST Austria.
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: Matilda
  full_name: Peruzzo, Matilda
  id: 3F920B30-F248-11E8-B48F-1D18A9856A87
  last_name: Peruzzo
  orcid: 0000-0002-3415-4628
- first_name: Farid
  full_name: Hassani, Farid
  id: 2AED110C-F248-11E8-B48F-1D18A9856A87
  last_name: Hassani
  orcid: 0000-0001-6937-5773
- first_name: Gregory
  full_name: Szep, Gregory
  last_name: Szep
- first_name: Andrea
  full_name: Trioni, Andrea
  id: 42F71B44-F248-11E8-B48F-1D18A9856A87
  last_name: Trioni
- first_name: Elena
  full_name: Redchenko, Elena
  id: 2C21D6E8-F248-11E8-B48F-1D18A9856A87
  last_name: Redchenko
- first_name: Martin
  full_name: Zemlicka, Martin
  id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87
  last_name: Zemlicka
  orcid: 0009-0005-0878-3032
- first_name: Johannes M
  full_name: Fink, Johannes M
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
citation:
  ama: 'Peruzzo M, Hassani F, Szep G, et al. Geometric superinductance qubits: Controlling
    phase delocalization across a single Josephson junction. <i>PRX Quantum</i>. 2021;2(4):040341.
    doi:<a href="https://doi.org/10.1103/PRXQuantum.2.040341">10.1103/PRXQuantum.2.040341</a>'
  apa: 'Peruzzo, M., Hassani, F., Szep, G., Trioni, A., Redchenko, E., Zemlicka, M.,
    &#38; Fink, J. M. (2021). Geometric superinductance qubits: Controlling phase
    delocalization across a single Josephson junction. <i>PRX Quantum</i>. American
    Physical Society. <a href="https://doi.org/10.1103/PRXQuantum.2.040341">https://doi.org/10.1103/PRXQuantum.2.040341</a>'
  chicago: 'Peruzzo, Matilda, Farid Hassani, Gregory Szep, Andrea Trioni, Elena Redchenko,
    Martin Zemlicka, and Johannes M Fink. “Geometric Superinductance Qubits: Controlling
    Phase Delocalization across a Single Josephson Junction.” <i>PRX Quantum</i>.
    American Physical Society, 2021. <a href="https://doi.org/10.1103/PRXQuantum.2.040341">https://doi.org/10.1103/PRXQuantum.2.040341</a>.'
  ieee: 'M. Peruzzo <i>et al.</i>, “Geometric superinductance qubits: Controlling
    phase delocalization across a single Josephson junction,” <i>PRX Quantum</i>,
    vol. 2, no. 4. American Physical Society, p. 040341, 2021.'
  ista: 'Peruzzo M, Hassani F, Szep G, Trioni A, Redchenko E, Zemlicka M, Fink JM.
    2021. Geometric superinductance qubits: Controlling phase delocalization across
    a single Josephson junction. PRX Quantum. 2(4), 040341.'
  mla: 'Peruzzo, Matilda, et al. “Geometric Superinductance Qubits: Controlling Phase
    Delocalization across a Single Josephson Junction.” <i>PRX Quantum</i>, vol. 2,
    no. 4, American Physical Society, 2021, p. 040341, doi:<a href="https://doi.org/10.1103/PRXQuantum.2.040341">10.1103/PRXQuantum.2.040341</a>.'
  short: M. Peruzzo, F. Hassani, G. Szep, A. Trioni, E. Redchenko, M. Zemlicka, J.M.
    Fink, PRX Quantum 2 (2021) 040341.
corr_author: '1'
date_created: 2021-08-17T08:14:18Z
date_published: 2021-11-24T00:00:00Z
date_updated: 2026-04-15T06:41:46Z
day: '24'
ddc:
- '530'
department:
- _id: JoFi
- _id: NanoFab
- _id: M-Shop
doi: 10.1103/PRXQuantum.2.040341
ec_funded: 1
external_id:
  arxiv:
  - '2106.05882'
  isi:
  - '000723015100001'
file:
- access_level: open_access
  checksum: 36eb41ea43d8ca22b0efab12419e4eb2
  content_type: application/pdf
  creator: cchlebak
  date_created: 2022-01-18T11:29:33Z
  date_updated: 2022-01-18T11:29:33Z
  file_id: '10641'
  file_name: 2021_PRXQuantum_Peruzzo.pdf
  file_size: 4247422
  relation: main_file
  success: 1
file_date_updated: 2022-01-18T11:29:33Z
has_accepted_license: '1'
intvolume: '         2'
isi: 1
issue: '4'
keyword:
- quantum physics
- mesoscale and nanoscale physics
language:
- iso: eng
month: '11'
oa: 1
oa_version: Published Version
page: '040341'
project:
- _id: 2564DBCA-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '665385'
  name: International IST Doctoral Program
- _id: 2622978C-B435-11E9-9278-68D0E5697425
  name: Hybrid Semiconductor - Superconductor Quantum Devices
- _id: bdb108fd-d553-11ed-ba76-83dc74a9864f
  grant_number: F07105
  name: QUANTUM INFORMATION SYSTEMS BEYOND CLASSICAL CAPABILITIES / P5- Integration
    of Superconducting Quantum Circuits
publication: PRX Quantum
publication_identifier:
  eissn:
  - 2691-3399
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
related_material:
  record:
  - id: '13057'
    relation: research_data
    status: public
  - id: '9920'
    relation: dissertation_contains
    status: public
  - id: '17133'
    relation: dissertation_contains
    status: public
scopus_import: '1'
status: public
title: 'Geometric superinductance qubits: Controlling phase delocalization across
  a single Josephson junction'
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: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 2
year: '2021'
...