---
_id: '1764'
abstract:
- lang: eng
  text: Quantum theory predicts that empty space is not truly empty. Even in the absence
    of any particles or radiation, in pure vacuum, virtual particles are constantly
    created and annihilated. In an electromagnetic field, the presence of virtual
    photons manifests itself as a small renormalization of the energy of a quantum
    system, known as the Lamb shift. We present an experimental observation of the
    Lamb shift in a solid-state system. The strong dispersive coupling of a superconducting
    electronic circuit acting as a quantum bit (qubit) to the vacuum field in a transmission-line
    resonator leads to measurable Lamb shifts of up to 1.4% of the qubit transition
    frequency. The qubit is also observed to couple more strongly to the vacuum field
    than to a single photon inside the cavity, an effect that is explained by taking
    into account the limited anharmonicity of the higher excited qubit states.
acknowledgement: This work was supported by the Swiss National Science Foundation
  and ETHZ. P.J.L. was supported by the European Commission with a Marie Curie Intra-European
  Fellowship. A.B. was supported by the Natural Sciences and Engineering Research
  Council of Canada, Canadian Institute for Advanced Research, and Fonds Québécois
  de la Recherche sur la Nature et les Technologies
author:
- first_name: A
  full_name: Fragner, A
  last_name: Fragner
- first_name: M
  full_name: Göppl, M
  last_name: Göppl
- first_name: Johannes M
  full_name: Johannes Fink
  id: 4B591CBA-F248-11E8-B48F-1D18A9856A87
  last_name: Fink
  orcid: 0000-0001-8112-028X
- first_name: Matthias
  full_name: Baur, Matthias P
  last_name: Baur
- first_name: R
  full_name: Bianchetti, R
  last_name: Bianchetti
- first_name: Peter
  full_name: Leek, Peter J
  last_name: Leek
- first_name: Alexandre
  full_name: Blais, Alexandre
  last_name: Blais
- first_name: Andreas
  full_name: Wallraff, Andreas
  last_name: Wallraff
citation:
  ama: Fragner A, Göppl M, Fink JM, et al. Resolving vacuum fluctuations in an electrical
    circuit by measuring the lamb shift. <i>Science</i>. 2008;322(5906):1357-1360.
    doi:<a href="https://doi.org/10.1126/science.1164482">10.1126/science.1164482</a>
  apa: Fragner, A., Göppl, M., Fink, J. M., Baur, M., Bianchetti, R., Leek, P., …
    Wallraff, A. (2008). Resolving vacuum fluctuations in an electrical circuit by
    measuring the lamb shift. <i>Science</i>. American Association for the Advancement
    of Science. <a href="https://doi.org/10.1126/science.1164482">https://doi.org/10.1126/science.1164482</a>
  chicago: Fragner, A, M Göppl, Johannes M Fink, Matthias Baur, R Bianchetti, Peter
    Leek, Alexandre Blais, and Andreas Wallraff. “Resolving Vacuum Fluctuations in
    an Electrical Circuit by Measuring the Lamb Shift.” <i>Science</i>. American Association
    for the Advancement of Science, 2008. <a href="https://doi.org/10.1126/science.1164482">https://doi.org/10.1126/science.1164482</a>.
  ieee: A. Fragner <i>et al.</i>, “Resolving vacuum fluctuations in an electrical
    circuit by measuring the lamb shift,” <i>Science</i>, vol. 322, no. 5906. American
    Association for the Advancement of Science, pp. 1357–1360, 2008.
  ista: Fragner A, Göppl M, Fink JM, Baur M, Bianchetti R, Leek P, Blais A, Wallraff
    A. 2008. Resolving vacuum fluctuations in an electrical circuit by measuring the
    lamb shift. Science. 322(5906), 1357–1360.
  mla: Fragner, A., et al. “Resolving Vacuum Fluctuations in an Electrical Circuit
    by Measuring the Lamb Shift.” <i>Science</i>, vol. 322, no. 5906, American Association
    for the Advancement of Science, 2008, pp. 1357–60, doi:<a href="https://doi.org/10.1126/science.1164482">10.1126/science.1164482</a>.
  short: A. Fragner, M. Göppl, J.M. Fink, M. Baur, R. Bianchetti, P. Leek, A. Blais,
    A. Wallraff, Science 322 (2008) 1357–1360.
date_created: 2018-12-11T11:53:53Z
date_published: 2008-11-28T00:00:00Z
date_updated: 2021-01-12T06:53:03Z
day: '28'
doi: 10.1126/science.1164482
extern: 1
intvolume: '       322'
issue: '5906'
month: '11'
page: 1357 - 1360
publication: Science
publication_status: published
publisher: American Association for the Advancement of Science
publist_id: '5357'
quality_controlled: 0
status: public
title: Resolving vacuum fluctuations in an electrical circuit by measuring the lamb
  shift
type: journal_article
volume: 322
year: '2008'
...