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Cited by 824Cosmology and Gravitation TheoriesGalaxies: Formation, Evolution, PhenomenaAdvanced Mathematical Theories and Applications

Further Evidence for Cosmological Evolution of the Fine Structure Constant

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Webb, J. K., Murphy, M. T., Flambaum, V. V., Dzuba, V. A., Barrow, J. D., Churchill, C. W., Prochaska, J. X., Wolfe, A. M.·2001·Physical Review Letters
DOI 10.1103/physrevlett.87.091301
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Abstract

We describe the results of a search for time variability of the fine structure constant $\ensuremath{\alpha}$ using absorption systems in the spectra of distant quasars. Three large optical data sets and two $21\mathrm{cm}$ and mm absorption systems provide four independent samples, spanning $\ensuremath{\sim}23%$ to $87%$ of the age of the universe. Each sample yields a smaller $\ensuremath{\alpha}$ in the past and the optical sample shows a $4\ensuremath{\sigma}$ deviation: $\ensuremath{\Delta}\ensuremath{\alpha}/\ensuremath{\alpha}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}0.72\ifmmode\pm\else\textpm\fi{}0.18\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ over the redshift range $0.5<z<3.5$. We find no systematic effects which can explain our results. The only potentially significant systematic effects push $\ensuremath{\Delta}\ensuremath{\alpha}/\ensuremath{\alpha}$ towards positive values; i.e., our results would become more significant were we to correct for them.

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  • The result was later confirmed by Murphy et al. (2001c) and Webb et al. (2001) from a reanalysis of the initial sample and by including new optical QSO data to reach 28 absorption systems with redshift z = 0.5-1.8 plus 18 damped Lyman-alpha absorption systems towards 13 QSO plus 21 Si IV absorption systems toward 13 QSO.

    “It was later confirmed by (Murphy et al. 2001c;Webb et al. 2001) from a reanalysis of the initial sample and by including new optical QSO data to reach 28 absorption systems with redshift z ¼ 0:5 À 1:8 plus 18 damped Lyman-a absorption systems towards 13 QSO plus 21 Si IV absorption systems toward 13 QSO.”

    From Fundamental constants: from measurement to the universe, a window on gravitation and cosmology (2025) · cites this paper as Webb et al. 2001

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References 44 · Cited by 824

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Authors
Webb, J. K., Murphy, M. T., Flambaum, V. V., Dzuba, V. A., Barrow, J. D., Churchill, C. W., Prochaska, J. X., & Wolfe, A. M.
Affiliations
  • UNSW Sydney (AU)
  • University of Cambridge (GB)
  • Pennsylvania State University (US)
  • Carnegie Observatories (US)
  • University of California San Diego (US)
ORCID
Venue
Physical Review Letters
Publisher
American Physical Society (APS)
Published
2001-08-09
Volume
87
Issue
9
Pages
091301-091301
ISSN
  • 0031-9007 (ISSN-L)
  • 1079-7114
DOI
10.1103/physrevlett.87.091301
OpenAlex
W2024972176
Cited by
824
References
44
Citations by year
2026: 5 · 2025: 10 · 2024: 13 · 2023: 18 · 2022: 16 · 2021: 18 · 2020: 9 · 2019: 9 · 2018: 10 · 2017: 25 · 2016: 17 · 2015: 21 · 2014: 24 · 2013: 27 · 2012: 23
FWCI
57.12
Type
journal article
Language
en
Open access
Licence
link.aps.org/licenses/aps-default-license (vor)
Locations
  • Physical Review Letters (publishedVersion)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • UNSWorks (UNSW Sydney) (submittedVersion, cc-by-nc-nd)
  • CERN Document Server (European Organization for Nuclear Research) (submittedVersion)
  • Figshare (submittedVersion, cc-by)
  • Swinburne figshare (Swinburne University of Technology) (submittedVersion)
  • UNSWorks (University of New South Wales, Sydney, Australia) (submittedVersion, cc-by-nc-nd)
  • arXiv (Cornell University)
  • Swinburne figshare (Swinburne University of Technology)
Funders
  • National Science Foundation (0071257)
  • John Templeton Foundation
  • University of New South Wales
Topics
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Cosmology and Gravitation Theories
  • Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Galaxies: Formation, Evolution, Phenomena
  • Physical Sciences › Physics and Astronomy › Statistical and Nonlinear Physics › Advanced Mathematical Theories and Applications
Keywords
fine-structure constant, cosmological evolution, quasar absorption lines, 21 cm absorption, systematic effects, redshift evolution

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