2021/01/20 by V. C. Tavares, Vasco Capela Tavares, C. J. A. P. Martins
Physics and Astronomy · #Black Holes and Theoretical Physics #Chaplygin gas #Cosmological constant #Cosmology #Cosmology and Gravitation Theories #Dark energy #Dimensionless quantity #Equation of state #Galaxies: Formation, Evolution, Phenomena #Lambda #Mathematical physics #Physics #Quantum mechanics #Tachyon #astro-ph.CO #gr-qc #hep-ph
paper · pdf · doi:10.1103/physrevd.103.023525
published as Phys.Rev. D 103 (2021) 023525 · 15 pages, 6 figures
openalex publication_date 2021/01/20 · arxiv created 2021/01/21 · arxiv updated 2021/01/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the cosmological consequences of a class of Dirac-Born-Infeld models, and assess their viability as a candidate for the recent acceleration of the Universe. The model includes both the rolling tachyon field and the generalized Chaplygin gas models as particular limits, and phenomenologically each of these provides a possible mechanism for a deviation of the value of the dark energy equation of state from its canonical (cosmological constant) value. The field-dependent potential that is characteristic of the rolling tachyon also leads to variations of the fine-structure constant \ensuremathα, implying that the model can be constrained both by standard cosmological probes and by astrophysical measurements of \ensuremathα. Our analysis, using the latest available low-redshfit data and local constraints from atomic clock and weak equivalence principle experiments, shows that the two possible deviations of the dark energy equation of state are constrained to be log10(1+w0)V<\ensuremath-7.85 and log10(1+w0)C<\ensuremath-0.85, respectively for the rolling tachyon and Chaplygin components, both being at the 95.4% confidence level (although the latter depends on the choice of priors, in a way that we quantify). Alternatively, the 95.4% confidence level bound on the dimensionless slope of the potential is log10\ensuremathλ<\ensuremath-5.36. This confirms previous analyses indicating that in these models the potential needs to be extremely flat.