---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
_id: '18602'
abstract:
- lang: eng
  text: Semiconductor quantum dots (QDs) in planar germanium (Ge) heterostructures
    have emerged as front-runners for future hole-based quantum processors. Here,
    we present strong coupling between a hole charge qubit, defined in a double quantum
    dot (DQD) in planar Ge, and microwave photons in a high-impedance (Zr = 1.3 kΩ)
    resonator based on an array of superconducting quantum interference devices (SQUIDs).
    Our investigation reveals vacuum-Rabi splittings with coupling strengths up to
    g0/2π = 260 MHz, and a cooperativity of C ~ 100, dependent on DQD tuning. Furthermore,
    utilizing the frequency tunability of our resonator, we explore the quenched energy
    splitting associated with strong Coulomb correlation effects in Ge QDs. The observed
    enhanced coherence of the strongly correlated excited state signals the presence
    of distinct symmetries within related spin functions, serving as a precursor to
    the strong coupling between photons and spin-charge hybrid qubits in planar Ge.
    This work paves the way towards coherent quantum connections between remote hole
    qubits in planar Ge, required to scale up hole-based quantum processors.
acknowledgement: The authors thank Simone Frasca, Vincent Jouanny, Guillaume Beaulieu,
  Camille Roy, Dominic Dahinden, Davide Lombardo, Daniel Chrastina, and Siddhart Gautam
  for contributing to some cleanroom fabrication steps, the measurement setup, device
  simulations, data analysis, and for the useful discussions. P.S. acknowledges support
  from the Swiss National Science Foundation (SNSF) through the grants Ref. No. 200021
  200418 and Ref. No. 206021_205335, and from the Swiss State Secretariat for Education,
  Research and Innovation (SERI) under contract number 01042765 SEFRI MB22.00081.
  W.J. acknowledges support from the EPFL QSE Postdoctoral Fellowship Grant. S.B.,
  D.L., and P.S. acknowledge support from the NCCR Spin Qubit in Silicon (NCCR-SPIN)
  Grant No. 51NF40-180604. M.J., G.K., G.I., and S.C. acknowledge support from the
  Horizon Europe Project IGNITE ID 101070193. G.K. acknowledges support from the FWF
  via the P32235 and I05060 projects.
article_number: '10177'
article_processing_charge: Yes
article_type: original
author:
- first_name: Franco
  full_name: De Palma, Franco
  last_name: De Palma
- first_name: Fabian
  full_name: Oppliger, Fabian
  last_name: Oppliger
- first_name: Wonjin
  full_name: Jang, Wonjin
  last_name: Jang
- first_name: Stefano
  full_name: Bosco, Stefano
  last_name: Bosco
- first_name: Marian
  full_name: Janik, Marian
  id: 396A1950-F248-11E8-B48F-1D18A9856A87
  last_name: Janik
  orcid: 0009-0003-9037-8831
- first_name: Stefano
  full_name: Calcaterra, Stefano
  last_name: Calcaterra
- first_name: Georgios
  full_name: Katsaros, Georgios
  id: 38DB5788-F248-11E8-B48F-1D18A9856A87
  last_name: Katsaros
  orcid: 0000-0001-8342-202X
- first_name: Giovanni
  full_name: Isella, Giovanni
  last_name: Isella
- first_name: Daniel
  full_name: Loss, Daniel
  last_name: Loss
- first_name: Pasquale
  full_name: Scarlino, Pasquale
  last_name: Scarlino
citation:
  ama: De Palma F, Oppliger F, Jang W, et al. Strong hole-photon coupling in planar
    Ge for probing charge degree and strongly correlated states. <i>Nature Communications</i>.
    2024;15. doi:<a href="https://doi.org/10.1038/s41467-024-54520-7">10.1038/s41467-024-54520-7</a>
  apa: De Palma, F., Oppliger, F., Jang, W., Bosco, S., Janik, M., Calcaterra, S.,
    … Scarlino, P. (2024). Strong hole-photon coupling in planar Ge for probing charge
    degree and strongly correlated states. <i>Nature Communications</i>. Springer
    Nature. <a href="https://doi.org/10.1038/s41467-024-54520-7">https://doi.org/10.1038/s41467-024-54520-7</a>
  chicago: De Palma, Franco, Fabian Oppliger, Wonjin Jang, Stefano Bosco, Marian Janik,
    Stefano Calcaterra, Georgios Katsaros, Giovanni Isella, Daniel Loss, and Pasquale
    Scarlino. “Strong Hole-Photon Coupling in Planar Ge for Probing Charge Degree
    and Strongly Correlated States.” <i>Nature Communications</i>. Springer Nature,
    2024. <a href="https://doi.org/10.1038/s41467-024-54520-7">https://doi.org/10.1038/s41467-024-54520-7</a>.
  ieee: F. De Palma <i>et al.</i>, “Strong hole-photon coupling in planar Ge for probing
    charge degree and strongly correlated states,” <i>Nature Communications</i>, vol.
    15. Springer Nature, 2024.
  ista: De Palma F, Oppliger F, Jang W, Bosco S, Janik M, Calcaterra S, Katsaros G,
    Isella G, Loss D, Scarlino P. 2024. Strong hole-photon coupling in planar Ge for
    probing charge degree and strongly correlated states. Nature Communications. 15,
    10177.
  mla: De Palma, Franco, et al. “Strong Hole-Photon Coupling in Planar Ge for Probing
    Charge Degree and Strongly Correlated States.” <i>Nature Communications</i>, vol.
    15, 10177, Springer Nature, 2024, doi:<a href="https://doi.org/10.1038/s41467-024-54520-7">10.1038/s41467-024-54520-7</a>.
  short: F. De Palma, F. Oppliger, W. Jang, S. Bosco, M. Janik, S. Calcaterra, G.
    Katsaros, G. Isella, D. Loss, P. Scarlino, Nature Communications 15 (2024).
das_tickbox: '1'
dataavailabilitystatement: The datasets generated during the current study are available
  in Zenodo with the identifier https://doi.org/10.5281/zenodo.13935167.
date_created: 2024-12-01T23:01:53Z
date_published: 2024-12-01T00:00:00Z
date_updated: 2026-10-02T11:02:23Z
day: '01'
ddc:
- '530'
department:
- _id: GeKa
doi: 10.1038/s41467-024-54520-7
external_id:
  isi:
  - '001362684200001'
  pmid:
  - '39580488'
file:
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  creator: dernst
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  date_updated: 2024-12-03T11:00:15Z
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fulldoi: https://doi.org/10.1038/s41467-024-54520-7
has_accepted_license: '1'
intvolume: '        15'
isi: 1
language:
- iso: eng
month: '12'
oa: 1
oa_version: Published Version
pmid: 1
project:
- _id: 237B3DA4-32DE-11EA-91FC-C7463DDC885E
  call_identifier: FWF
  grant_number: P32235
  name: Towards scalable hut wire quantum devices
- _id: c0977eea-5a5b-11eb-8a69-a862db0cf4d1
  grant_number: I05060
  name: High impedance circuit quantum electrodynamics with hole spins
publication: Nature Communications
publication_identifier:
  eissn:
  - 2041-1723
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
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  - id: '23037'
    relation: research_data
    status: public
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Strong hole-photon coupling in planar Ge for probing charge degree and strongly
  correlated states
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: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 15
year: '2024'
...