---
_id: '13227'
abstract:
- lang: eng
  text: Currently available quantum processors are dominated by noise, which severely
    limits their applicability and motivates the search for new physical qubit encodings.
    In this work, we introduce the inductively shunted transmon, a weakly flux-tunable
    superconducting qubit that offers charge offset protection for all levels and
    a 20-fold reduction in flux dispersion compared to the state-of-the-art resulting
    in a constant coherence over a full flux quantum. The parabolic confinement provided
    by the inductive shunt as well as the linearity of the geometric superinductor
    facilitates a high-power readout that resolves quantum jumps with a fidelity and
    QND-ness of >90% and without the need for a Josephson parametric amplifier. Moreover,
    the device reveals quantum tunneling physics between the two prepared fluxon ground
    states with a measured average decay time of up to 3.5 h. In the future, fast
    time-domain control of the transition matrix elements could offer a new path forward
    to also achieve full qubit control in the decay-protected fluxon basis.
acknowledged_ssus:
- _id: M-Shop
- _id: NanoFab
acknowledgement: The authors thank J. Koch for discussions and support with the scQubits
  python package, I. Rozhansky and A. Poddubny for important insights into photon-assisted
  tunneling, S. Barzanjeh and G. Arnold for theory, E. Redchenko, S. Pepic, the MIBA
  workshop and the IST nanofabrication facility for technical contributions, as well
  as L. Drmic, P. Zielinski and R. Sett for software development. We acknowledge the
  prompt support of Quantum Machines to implement active state preparation with their
  OPX+. This work was supported by a NOMIS foundation research grant (J.F.), the Austrian
  Science Fund (FWF) through BeyondC F7105 (J.F.) and IST Austria.
article_number: '3968'
article_processing_charge: No
article_type: original
author:
- first_name: Farid
  full_name: Hassani, Farid
  id: 2AED110C-F248-11E8-B48F-1D18A9856A87
  last_name: Hassani
  orcid: 0000-0001-6937-5773
- first_name: Matilda
  full_name: Peruzzo, Matilda
  id: 3F920B30-F248-11E8-B48F-1D18A9856A87
  last_name: Peruzzo
  orcid: 0000-0002-3415-4628
- first_name: Lucky
  full_name: Kapoor, Lucky
  id: 84b9700b-15b2-11ec-abd3-831089e67615
  last_name: Kapoor
- first_name: Andrea
  full_name: Trioni, Andrea
  id: 42F71B44-F248-11E8-B48F-1D18A9856A87
  last_name: Trioni
- first_name: Martin
  full_name: Zemlicka, Martin
  id: 2DCF8DE6-F248-11E8-B48F-1D18A9856A87
  last_name: Zemlicka
- 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: Hassani F, Peruzzo M, Kapoor L, Trioni A, Zemlicka M, Fink JM. Inductively
    shunted transmons exhibit noise insensitive plasmon states and a fluxon decay
    exceeding 3 hours. <i>Nature Communications</i>. 2023;14. doi:<a href="https://doi.org/10.1038/s41467-023-39656-2">10.1038/s41467-023-39656-2</a>
  apa: Hassani, F., Peruzzo, M., Kapoor, L., Trioni, A., Zemlicka, M., &#38; Fink,
    J. M. (2023). Inductively shunted transmons exhibit noise insensitive plasmon
    states and a fluxon decay exceeding 3 hours. <i>Nature Communications</i>. Springer
    Nature. <a href="https://doi.org/10.1038/s41467-023-39656-2">https://doi.org/10.1038/s41467-023-39656-2</a>
  chicago: Hassani, Farid, Matilda Peruzzo, Lucky Kapoor, Andrea Trioni, Martin Zemlicka,
    and Johannes M Fink. “Inductively Shunted Transmons Exhibit Noise Insensitive
    Plasmon States and a Fluxon Decay Exceeding 3 Hours.” <i>Nature Communications</i>.
    Springer Nature, 2023. <a href="https://doi.org/10.1038/s41467-023-39656-2">https://doi.org/10.1038/s41467-023-39656-2</a>.
  ieee: F. Hassani, M. Peruzzo, L. Kapoor, A. Trioni, M. Zemlicka, and J. M. Fink,
    “Inductively shunted transmons exhibit noise insensitive plasmon states and a
    fluxon decay exceeding 3 hours,” <i>Nature Communications</i>, vol. 14. Springer
    Nature, 2023.
  ista: Hassani F, Peruzzo M, Kapoor L, Trioni A, Zemlicka M, Fink JM. 2023. Inductively
    shunted transmons exhibit noise insensitive plasmon states and a fluxon decay
    exceeding 3 hours. Nature Communications. 14, 3968.
  mla: Hassani, Farid, et al. “Inductively Shunted Transmons Exhibit Noise Insensitive
    Plasmon States and a Fluxon Decay Exceeding 3 Hours.” <i>Nature Communications</i>,
    vol. 14, 3968, Springer Nature, 2023, doi:<a href="https://doi.org/10.1038/s41467-023-39656-2">10.1038/s41467-023-39656-2</a>.
  short: F. Hassani, M. Peruzzo, L. Kapoor, A. Trioni, M. Zemlicka, J.M. Fink, Nature
    Communications 14 (2023).
date_created: 2023-07-16T22:01:08Z
date_published: 2023-07-05T00:00:00Z
date_updated: 2023-12-13T11:32:25Z
day: '05'
ddc:
- '530'
department:
- _id: JoFi
doi: 10.1038/s41467-023-39656-2
external_id:
  isi:
  - '001024729900009'
  pmid:
  - '37407570'
file:
- access_level: open_access
  checksum: a85773b5fe23516f60f7d5d31b55c200
  content_type: application/pdf
  creator: dernst
  date_created: 2023-07-18T08:43:07Z
  date_updated: 2023-07-18T08:43:07Z
  file_id: '13248'
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file_date_updated: 2023-07-18T08:43:07Z
has_accepted_license: '1'
intvolume: '        14'
isi: 1
language:
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month: '07'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 26927A52-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: F07105
  name: Integrating superconducting quantum circuits
- _id: 2622978C-B435-11E9-9278-68D0E5697425
  name: Hybrid Semiconductor - Superconductor Quantum Devices
publication: Nature Communications
publication_identifier:
  eissn:
  - 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Inductively shunted transmons exhibit noise insensitive plasmon states and
  a fluxon decay exceeding 3 hours
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: 14
year: '2023'
...
---
_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
- 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.
date_created: 2021-08-17T08:14:18Z
date_published: 2021-11-24T00:00:00Z
date_updated: 2023-09-07T13:31:22Z
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: 26927A52-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: F07105
  name: Integrating superconducting quantum circuits
- _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
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
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: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 2
year: '2021'
...
---
_id: '8038'
abstract:
- lang: eng
  text: Microelectromechanical systems and integrated photonics provide the basis
    for many reliable and compact circuit elements in modern communication systems.
    Electro-opto-mechanical devices are currently one of the leading approaches to
    realize ultra-sensitive, low-loss transducers for an emerging quantum information
    technology. Here we present an on-chip microwave frequency converter based on
    a planar aluminum on silicon nitride platform that is compatible with slot-mode
    coupled photonic crystal cavities. We show efficient frequency conversion between
    two propagating microwave modes mediated by the radiation pressure interaction
    with a metalized dielectric nanobeam oscillator. We achieve bidirectional coherent
    conversion with a total device efficiency of up to ~60%, a dynamic range of 2
    × 10^9 photons/s and an instantaneous bandwidth of up to 1.7 kHz. A high fidelity
    quantum state transfer would be possible if the drive dependent output noise of
    currently ~14 photons s^−1 Hz^−1 is further reduced. Such a silicon nitride based
    transducer is in situ reconfigurable and could be used for on-chip classical and
    quantum signal routing and filtering, both for microwave and hybrid microwave-optical
    applications.
article_number: '034011'
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Johannes M
  full_name: Fink, Johannes M
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
- first_name: M.
  full_name: Kalaee, M.
  last_name: Kalaee
- first_name: R.
  full_name: Norte, R.
  last_name: Norte
- first_name: A.
  full_name: Pitanti, A.
  last_name: Pitanti
- first_name: O.
  full_name: Painter, O.
  last_name: Painter
citation:
  ama: Fink JM, Kalaee M, Norte R, Pitanti A, Painter O. Efficient microwave frequency
    conversion mediated by a photonics compatible silicon nitride nanobeam oscillator.
    <i>Quantum Science and Technology</i>. 2020;5(3). doi:<a href="https://doi.org/10.1088/2058-9565/ab8dce">10.1088/2058-9565/ab8dce</a>
  apa: Fink, J. M., Kalaee, M., Norte, R., Pitanti, A., &#38; Painter, O. (2020).
    Efficient microwave frequency conversion mediated by a photonics compatible silicon
    nitride nanobeam oscillator. <i>Quantum Science and Technology</i>. IOP Publishing.
    <a href="https://doi.org/10.1088/2058-9565/ab8dce">https://doi.org/10.1088/2058-9565/ab8dce</a>
  chicago: Fink, Johannes M, M. Kalaee, R. Norte, A. Pitanti, and O. Painter. “Efficient
    Microwave Frequency Conversion Mediated by a Photonics Compatible Silicon Nitride
    Nanobeam Oscillator.” <i>Quantum Science and Technology</i>. IOP Publishing, 2020.
    <a href="https://doi.org/10.1088/2058-9565/ab8dce">https://doi.org/10.1088/2058-9565/ab8dce</a>.
  ieee: J. M. Fink, M. Kalaee, R. Norte, A. Pitanti, and O. Painter, “Efficient microwave
    frequency conversion mediated by a photonics compatible silicon nitride nanobeam
    oscillator,” <i>Quantum Science and Technology</i>, vol. 5, no. 3. IOP Publishing,
    2020.
  ista: Fink JM, Kalaee M, Norte R, Pitanti A, Painter O. 2020. Efficient microwave
    frequency conversion mediated by a photonics compatible silicon nitride nanobeam
    oscillator. Quantum Science and Technology. 5(3), 034011.
  mla: Fink, Johannes M., et al. “Efficient Microwave Frequency Conversion Mediated
    by a Photonics Compatible Silicon Nitride Nanobeam Oscillator.” <i>Quantum Science
    and Technology</i>, vol. 5, no. 3, 034011, IOP Publishing, 2020, doi:<a href="https://doi.org/10.1088/2058-9565/ab8dce">10.1088/2058-9565/ab8dce</a>.
  short: J.M. Fink, M. Kalaee, R. Norte, A. Pitanti, O. Painter, Quantum Science and
    Technology 5 (2020).
date_created: 2020-06-29T07:59:35Z
date_published: 2020-05-25T00:00:00Z
date_updated: 2024-08-07T07:11:51Z
day: '25'
ddc:
- '530'
department:
- _id: JoFi
doi: 10.1088/2058-9565/ab8dce
ec_funded: 1
external_id:
  isi:
  - '000539300800001'
file:
- access_level: open_access
  checksum: 8f25f05053f511f892ae8fa93f341e61
  content_type: application/pdf
  creator: cziletti
  date_created: 2020-06-30T10:29:10Z
  date_updated: 2020-07-14T12:48:08Z
  file_id: '8072'
  file_name: 2020_QuantumSciTechnol_Fink.pdf
  file_size: 2600967
  relation: main_file
file_date_updated: 2020-07-14T12:48:08Z
has_accepted_license: '1'
intvolume: '         5'
isi: 1
issue: '3'
language:
- iso: eng
month: '05'
oa: 1
oa_version: Published Version
project:
- _id: 26336814-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '758053'
  name: A Fiber Optic Transceiver for Superconducting Qubits
- _id: 26927A52-B435-11E9-9278-68D0E5697425
  call_identifier: FWF
  grant_number: F07105
  name: Integrating superconducting quantum circuits
- _id: 257EB838-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '732894'
  name: Hybrid Optomechanical Technologies
- _id: 2622978C-B435-11E9-9278-68D0E5697425
  name: Hybrid Semiconductor - Superconductor Quantum Devices
publication: Quantum Science and Technology
publication_identifier:
  eissn:
  - '20589565'
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: Efficient microwave frequency conversion mediated by a photonics compatible
  silicon nitride nanobeam oscillator
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: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 5
year: '2020'
...