---
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OA_type: hybrid
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abstract:
- lang: eng
  text: Josephson junction (JJ) chains combine the coherence of superconductivity
    with the controllability of microwave-frequency circuits, making them a powerful
    platform for circuit quantum electrodynamics. In this work, we consider a long
    JJ chain that effectively realizes a multimode cavity with nonlinear dispersion
    and additional multimode interactions. Individual modes appearing due to the finite
    size of the chain can be experimentally probed via microwave spectroscopy, both
    in equilibrium and in driven far-from-equilibrium settings. We study the role
    of multimode interactions in degrading internal coherence—observable as excess
    linewidth—in both equilibrium and driven regimes. Focusing on two-into-two mode
    scattering as the leading relaxation process, we classify the relevant scattering
    processes and derive their expected temperature- and frequency-scaling under equilibrium
    conditions. For experimentally relevant parameters, we show that the equilibrium
    decay rate is dominated by nonresonant processes, however, weakly driving a particular
    set of modes out of equilibrium enhances resonant scattering, leading to observable
    signatures in the distribution function and linewidth. Finally, in the strong
    nonequilibrium regime, we report a crossover to a qualitatively different nonequilibrium
    steady state.
acknowledgement: We acknowledge useful discussions with Anton Bubis, Vladimir Manucharyan,
  Alexander Mirlin, and Thomas Scaffidi. We are grateful to Eli Levenson-Falk and
  Alexander Mirlin for their feedback on the manuscript. This research was supported
  in part by Grant NSF PHY-2309135 to the Kavli Institute for Theoretical Physics
  (KITP), and by the Austrian Science Fund (FWF) SFB F86.
article_number: '194501'
article_processing_charge: Yes (via OA deal)
article_type: original
arxiv: 1
author:
- first_name: Lucia
  full_name: Vigliotti, Lucia
  id: 539e1e1a-e604-11ee-a1df-f02b018e5c8c
  last_name: Vigliotti
- first_name: Andrew P
  full_name: Higginbotham, Andrew P
  id: 4AD6785A-F248-11E8-B48F-1D18A9856A87
  last_name: Higginbotham
  orcid: 0000-0003-2607-2363
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
citation:
  ama: Vigliotti L, Higginbotham AP, Serbyn M. Plasmon decay and nonequilibrium steady
    states in Josephson junction chains. <i>Physical Review B</i>. 2026;114(19). doi:<a
    href="https://doi.org/10.1103/cw3m-thsw">10.1103/cw3m-thsw</a>
  apa: Vigliotti, L., Higginbotham, A. P., &#38; Serbyn, M. (2026). Plasmon decay
    and nonequilibrium steady states in Josephson junction chains. <i>Physical Review
    B</i>. American Physical Society. <a href="https://doi.org/10.1103/cw3m-thsw">https://doi.org/10.1103/cw3m-thsw</a>
  chicago: Vigliotti, Lucia, Andrew P Higginbotham, and Maksym Serbyn. “Plasmon Decay
    and Nonequilibrium Steady States in Josephson Junction Chains.” <i>Physical Review
    B</i>. American Physical Society, 2026. <a href="https://doi.org/10.1103/cw3m-thsw">https://doi.org/10.1103/cw3m-thsw</a>.
  ieee: L. Vigliotti, A. P. Higginbotham, and M. Serbyn, “Plasmon decay and nonequilibrium
    steady states in Josephson junction chains,” <i>Physical Review B</i>, vol. 114,
    no. 19. American Physical Society, 2026.
  ista: Vigliotti L, Higginbotham AP, Serbyn M. 2026. Plasmon decay and nonequilibrium
    steady states in Josephson junction chains. Physical Review B. 114(19), 194501.
  mla: Vigliotti, Lucia, et al. “Plasmon Decay and Nonequilibrium Steady States in
    Josephson Junction Chains.” <i>Physical Review B</i>, vol. 114, no. 19, 194501,
    American Physical Society, 2026, doi:<a href="https://doi.org/10.1103/cw3m-thsw">10.1103/cw3m-thsw</a>.
  short: L. Vigliotti, A.P. Higginbotham, M. Serbyn, Physical Review B 114 (2026).
corr_author: '1'
das_tickbox: '1'
dataavailabilitystatement: 'The data and the source code that support the findings
  of this paper are openly available at: https://doi.org/10.5281/zenodo.19456426.'
date_created: 2026-10-02T08:33:31Z
date_published: 2026-10-01T00:00:00Z
date_updated: 2026-10-07T09:42:41Z
day: '01'
ddc:
- '530'
department:
- _id: MaSe
- _id: AnHi
doi: 10.1103/cw3m-thsw
external_id:
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  - '2603.06371'
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fulldoi: https://doi.org/10.1103/cw3m-thsw
has_accepted_license: '1'
intvolume: '       114'
issue: '19'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '10'
oa: 1
oa_version: Published Version
project:
- _id: 34a7f947-11ca-11ed-8bc3-c5dc2bbaae25
  grant_number: F8609
  name: 'Center for Correlated Quantum Materials and Solid State Quantum Systems:  Probing
    topology in circuits and quantum materials'
publication: Physical Review B
publication_identifier:
  eissn:
  - 2469-9969
  issn:
  - 2469-9950
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: Plasmon decay and nonequilibrium steady states in Josephson junction chains
tmp:
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type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 114
year: '2026'
...
---
DOAJ_listed: '1'
OA_place: publisher
OA_type: gold
PlanS_conform: '1'
_id: '21340'
abstract:
- lang: eng
  text: Equilibrium quantum systems are often described by a gas of weakly interacting
    normal modes. Bringing such systems far from equilibrium, however, can drastically
    enhance mode-to-mode interactions. Understanding the resulting liquid is a fundamental
    question for quantum statistical mechanics and a practical question for engineering
    driven quantum devices. To tackle this question, we probe the non-equilibrium
    kinetics of one-dimensional plasmons in a long chain of Josephson junctions. We
    introduce multimode spectroscopy to controllably study the departure from equilibrium,
    witnessing the evolution from pairwise coupling between plasma modes at weak driving
    to dramatic, high-order, cascaded couplings at strong driving. Scaling to many-mode
    drives, we stimulate interactions between hundreds of modes, resulting in near-continuum
    internal dynamics. Imaging the resulting non-equilibrium plasmon populations,
    we then resolve the nonlocal redistribution of energy in the response to a weak
    perturbation—an explicit verification of the emergence of a strongly interacting,
    non-equilibrium liquid of plasmons.
acknowledged_ssus:
- _id: NanoFab
- _id: M-Shop
acknowledgement: We thank V. Vitelli, M. Fruchart, and A. Burshstein for helpful input.
  We acknowledge technical support from the Nanofabrication Facility and the MIBA
  machine shop at IST Austria. This research was supported in part by grant NSF PHY-2309135
  to the Kavli Institute for Theoretical Physics (KITP), by the Austrian Science Fund
  (FWF) SFB F86, and by the NOMIS foundation.
article_number: eady7222
article_processing_charge: Yes
article_type: original
arxiv: 1
author:
- first_name: Anton
  full_name: Bubis, Anton
  id: 1f6212b5-f795-11ec-9c0c-de4780302890
  last_name: Bubis
- first_name: Lucia
  full_name: Vigliotti, Lucia
  id: 539e1e1a-e604-11ee-a1df-f02b018e5c8c
  last_name: Vigliotti
- first_name: Maksym
  full_name: Serbyn, Maksym
  id: 47809E7E-F248-11E8-B48F-1D18A9856A87
  last_name: Serbyn
  orcid: 0000-0002-2399-5827
- first_name: Andrew P
  full_name: Higginbotham, Andrew P
  id: 4AD6785A-F248-11E8-B48F-1D18A9856A87
  last_name: Higginbotham
  orcid: 0000-0003-2607-2363
citation:
  ama: Bubis A, Vigliotti L, Serbyn M, Higginbotham AP. Non-equilibrium plasmon liquid
    in a Josephson junction chain. <i>Science Advances</i>. 2026;12(7). doi:<a href="https://doi.org/10.1126/sciadv.ady7222">10.1126/sciadv.ady7222</a>
  apa: Bubis, A., Vigliotti, L., Serbyn, M., &#38; Higginbotham, A. P. (2026). Non-equilibrium
    plasmon liquid in a Josephson junction chain. <i>Science Advances</i>. AAAS. <a
    href="https://doi.org/10.1126/sciadv.ady7222">https://doi.org/10.1126/sciadv.ady7222</a>
  chicago: Bubis, Anton, Lucia Vigliotti, Maksym Serbyn, and Andrew P Higginbotham.
    “Non-Equilibrium Plasmon Liquid in a Josephson Junction Chain.” <i>Science Advances</i>.
    AAAS, 2026. <a href="https://doi.org/10.1126/sciadv.ady7222">https://doi.org/10.1126/sciadv.ady7222</a>.
  ieee: A. Bubis, L. Vigliotti, M. Serbyn, and A. P. Higginbotham, “Non-equilibrium
    plasmon liquid in a Josephson junction chain,” <i>Science Advances</i>, vol. 12,
    no. 7. AAAS, 2026.
  ista: Bubis A, Vigliotti L, Serbyn M, Higginbotham AP. 2026. Non-equilibrium plasmon
    liquid in a Josephson junction chain. Science Advances. 12(7), eady7222.
  mla: Bubis, Anton, et al. “Non-Equilibrium Plasmon Liquid in a Josephson Junction
    Chain.” <i>Science Advances</i>, vol. 12, no. 7, eady7222, AAAS, 2026, doi:<a
    href="https://doi.org/10.1126/sciadv.ady7222">10.1126/sciadv.ady7222</a>.
  short: A. Bubis, L. Vigliotti, M. Serbyn, A.P. Higginbotham, Science Advances 12
    (2026).
corr_author: '1'
date_created: 2026-02-22T20:47:38Z
date_published: 2026-02-13T00:00:00Z
date_updated: 2026-10-20T08:10:46Z
day: '13'
ddc:
- '530'
department:
- _id: MaSe
- _id: AnHi
- _id: GeKa
doi: 10.1126/sciadv.ady7222
external_id:
  arxiv:
  - '2504.09721'
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  date_created: 2026-02-24T07:23:32Z
  date_updated: 2026-02-24T07:23:32Z
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  file_size: 2775975
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file_date_updated: 2026-02-24T07:23:32Z
fulldoi: https://doi.org/10.1126/sciadv.ady7222
has_accepted_license: '1'
intvolume: '        12'
issue: '7'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
publication: Science Advances
publication_identifier:
  eissn:
  - 2375-2548
publication_status: published
publisher: AAAS
quality_controlled: '1'
status: public
title: Non-equilibrium plasmon liquid in a Josephson junction chain
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  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
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  short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 12
year: '2026'
...