---
_id: '1114'
abstract:
- lang: eng
  text: Nonequilibrium phase transitions exist in damped-driven open quantum systems
    when the continuous tuning of an external parameter leads to a transition between
    two robust steady states. In second-order transitions this change is abrupt at
    a critical point, whereas in first-order transitions the two phases can coexist
    in a critical hysteresis domain. Here, we report the observation of a first-order
    dissipative quantum phase transition in a driven circuit quantum electrodynamics
    system. It takes place when the photon blockade of the driven cavity-atom system
    is broken by increasing the drive power. The observed experimental signature is
    a bimodal phase space distribution with varying weights controlled by the drive
    strength. Our measurements show an improved stabilization of the classical attractors
    up to the millisecond range when the size of the quantum system is increased from
    one to three artificial atoms. The formation of such robust pointer states could
    be used for new quantum measurement schemes or to investigate multiphoton phases
    of finite-size, nonlinear, open quantum systems.
article_number: '011012'
article_processing_charge: Yes
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: András
  full_name: Dombi, András
  last_name: Dombi
- first_name: András
  full_name: Vukics, András
  last_name: Vukics
- first_name: Andreas
  full_name: Wallraff, Andreas
  last_name: Wallraff
- first_name: Peter
  full_name: Domokos, Peter
  last_name: Domokos
citation:
  ama: Fink JM, Dombi A, Vukics A, Wallraff A, Domokos P. Observation of the photon
    blockade breakdown phase transition. <i>Physical Review X</i>. 2017;7(1). doi:<a
    href="https://doi.org/10.1103/PhysRevX.7.011012">10.1103/PhysRevX.7.011012</a>
  apa: Fink, J. M., Dombi, A., Vukics, A., Wallraff, A., &#38; Domokos, P. (2017).
    Observation of the photon blockade breakdown phase transition. <i>Physical Review
    X</i>. American Physical Society. <a href="https://doi.org/10.1103/PhysRevX.7.011012">https://doi.org/10.1103/PhysRevX.7.011012</a>
  chicago: Fink, Johannes M, András Dombi, András Vukics, Andreas Wallraff, and Peter
    Domokos. “Observation of the Photon Blockade Breakdown Phase Transition.” <i>Physical
    Review X</i>. American Physical Society, 2017. <a href="https://doi.org/10.1103/PhysRevX.7.011012">https://doi.org/10.1103/PhysRevX.7.011012</a>.
  ieee: J. M. Fink, A. Dombi, A. Vukics, A. Wallraff, and P. Domokos, “Observation
    of the photon blockade breakdown phase transition,” <i>Physical Review X</i>,
    vol. 7, no. 1. American Physical Society, 2017.
  ista: Fink JM, Dombi A, Vukics A, Wallraff A, Domokos P. 2017. Observation of the
    photon blockade breakdown phase transition. Physical Review X. 7(1), 011012.
  mla: Fink, Johannes M., et al. “Observation of the Photon Blockade Breakdown Phase
    Transition.” <i>Physical Review X</i>, vol. 7, no. 1, 011012, American Physical
    Society, 2017, doi:<a href="https://doi.org/10.1103/PhysRevX.7.011012">10.1103/PhysRevX.7.011012</a>.
  short: J.M. Fink, A. Dombi, A. Vukics, A. Wallraff, P. Domokos, Physical Review
    X 7 (2017).
date_created: 2018-12-11T11:50:13Z
date_published: 2017-01-31T00:00:00Z
date_updated: 2025-07-10T11:50:07Z
day: '31'
ddc:
- '539'
department:
- _id: JoFi
doi: 10.1103/PhysRevX.7.011012
external_id:
  isi:
  - '000397450500001'
file:
- access_level: open_access
  content_type: application/pdf
  creator: system
  date_created: 2018-12-12T10:12:52Z
  date_updated: 2018-12-12T10:12:52Z
  file_id: '4972'
  file_name: IST-2017-753-v1+1_PhysRevX.7.011012.pdf
  file_size: 1172926
  relation: main_file
file_date_updated: 2018-12-12T10:12:52Z
has_accepted_license: '1'
intvolume: '         7'
isi: 1
issue: '1'
language:
- iso: eng
month: '01'
oa: 1
oa_version: Published Version
publication: Physical Review X
publication_identifier:
  issn:
  - 2160-3308
publication_status: published
publisher: American Physical Society
publist_id: '6252'
pubrep_id: '753'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Observation of the photon blockade breakdown phase transition
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: 7
year: '2017'
...