---
_id: '13119'
abstract:
- lang: eng
  text: A density wave (DW) is a fundamental type of long-range order in quantum matter
    tied to self-organization into a crystalline structure. The interplay of DW order
    with superfluidity can lead to complex scenarios that pose a great challenge to
    theoretical analysis. In the past decades, tunable quantum Fermi gases have served
    as model systems for exploring the physics of strongly interacting fermions, including
    most notably magnetic ordering1, pairing and superfluidity2, and the crossover
    from a Bardeen–Cooper–Schrieffer superfluid to a Bose–Einstein condensate3. Here,
    we realize a Fermi gas featuring both strong, tunable contact interactions and
    photon-mediated, spatially structured long-range interactions in a transversely
    driven high-finesse optical cavity. Above a critical long-range interaction strength,
    DW order is stabilized in the system, which we identify via its superradiant light-scattering
    properties. We quantitatively measure the variation of the onset of DW order as
    the contact interaction is varied across the Bardeen–Cooper–Schrieffer superfluid
    and Bose–Einstein condensate crossover, in qualitative agreement with a mean-field
    theory. The atomic DW susceptibility varies over an order of magnitude upon tuning
    the strength and the sign of the long-range interactions below the self-ordering
    threshold, demonstrating independent and simultaneous control over the contact
    and long-range interactions. Therefore, our experimental setup provides a fully
    tunable and microscopically controllable platform for the experimental study of
    the interplay of superfluidity and DW order.
acknowledgement: Open access funding provided by EPFL Lausanne.We acknowledge discussions
  with T. Donner and T. Esslinger. We thank G. del Pace and T. Bühler for their assistance
  in the final stages of the experiment. We acknowledge funding from the European
  Research Council under the European Union Horizon 2020 Research and Innovation Programme
  (Grant no. 714309) and the Swiss National Science Foundation (Grant no. 184654).
  F.M. acknowledges financial support from the Austrian Science Fund (Stand-Alone
  Project P 35891-N).
article_processing_charge: Yes (via OA deal)
article_type: original
author:
- first_name: Victor
  full_name: Helson, Victor
  last_name: Helson
- first_name: Timo
  full_name: Zwettler, Timo
  last_name: Zwettler
- first_name: Farokh
  full_name: Mivehvar, Farokh
  last_name: Mivehvar
- first_name: Elvia
  full_name: Colella, Elvia
  last_name: Colella
- first_name: Kevin Etienne Robert
  full_name: Roux, Kevin Etienne Robert
  id: 53f93ea2-803f-11ed-ab7e-b283135794ef
  last_name: Roux
- first_name: Hideki
  full_name: Konishi, Hideki
  last_name: Konishi
- first_name: Helmut
  full_name: Ritsch, Helmut
  last_name: Ritsch
- first_name: Jean Philippe
  full_name: Brantut, Jean Philippe
  last_name: Brantut
citation:
  ama: Helson V, Zwettler T, Mivehvar F, et al. Density-wave ordering in a unitary
    Fermi gas with photon-mediated interactions. <i>Nature</i>. 2023;618:716-720.
    doi:<a href="https://doi.org/10.1038/s41586-023-06018-3">10.1038/s41586-023-06018-3</a>
  apa: Helson, V., Zwettler, T., Mivehvar, F., Colella, E., Roux, K. E. R., Konishi,
    H., … Brantut, J. P. (2023). Density-wave ordering in a unitary Fermi gas with
    photon-mediated interactions. <i>Nature</i>. Springer Nature. <a href="https://doi.org/10.1038/s41586-023-06018-3">https://doi.org/10.1038/s41586-023-06018-3</a>
  chicago: Helson, Victor, Timo Zwettler, Farokh Mivehvar, Elvia Colella, Kevin Etienne
    Robert Roux, Hideki Konishi, Helmut Ritsch, and Jean Philippe Brantut. “Density-Wave
    Ordering in a Unitary Fermi Gas with Photon-Mediated Interactions.” <i>Nature</i>.
    Springer Nature, 2023. <a href="https://doi.org/10.1038/s41586-023-06018-3">https://doi.org/10.1038/s41586-023-06018-3</a>.
  ieee: V. Helson <i>et al.</i>, “Density-wave ordering in a unitary Fermi gas with
    photon-mediated interactions,” <i>Nature</i>, vol. 618. Springer Nature, pp. 716–720,
    2023.
  ista: Helson V, Zwettler T, Mivehvar F, Colella E, Roux KER, Konishi H, Ritsch H,
    Brantut JP. 2023. Density-wave ordering in a unitary Fermi gas with photon-mediated
    interactions. Nature. 618, 716–720.
  mla: Helson, Victor, et al. “Density-Wave Ordering in a Unitary Fermi Gas with Photon-Mediated
    Interactions.” <i>Nature</i>, vol. 618, Springer Nature, 2023, pp. 716–20, doi:<a
    href="https://doi.org/10.1038/s41586-023-06018-3">10.1038/s41586-023-06018-3</a>.
  short: V. Helson, T. Zwettler, F. Mivehvar, E. Colella, K.E.R. Roux, H. Konishi,
    H. Ritsch, J.P. Brantut, Nature 618 (2023) 716–720.
date_created: 2023-06-04T22:01:03Z
date_published: 2023-06-22T00:00:00Z
date_updated: 2023-11-14T13:02:50Z
day: '22'
ddc:
- '530'
department:
- _id: GeKa
doi: 10.1038/s41586-023-06018-3
external_id:
  isi:
  - '001001139300008'
file:
- access_level: open_access
  checksum: 4887a296e3b6f54e8c0b946cbfd24f49
  content_type: application/pdf
  creator: dernst
  date_created: 2023-11-14T13:00:19Z
  date_updated: 2023-11-14T13:00:19Z
  file_id: '14534'
  file_name: 2023_Nature_Helson.pdf
  file_size: 8156497
  relation: main_file
  success: 1
file_date_updated: 2023-11-14T13:00:19Z
has_accepted_license: '1'
intvolume: '       618'
isi: 1
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '06'
oa: 1
oa_version: Published Version
page: 716-720
publication: Nature
publication_identifier:
  eissn:
  - 1476-4687
  issn:
  - 0028-0836
publication_status: published
publisher: Springer Nature
quality_controlled: '1'
scopus_import: '1'
status: public
title: Density-wave ordering in a unitary Fermi gas with photon-mediated interactions
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: 618
year: '2023'
...