Constraining variations in the fine structure constant in the presence of early dark energy

Calabrese, E.; Menegoni, E.; Martins, C. J. A. P.; Melchiorri, A.; Rocha, G.

doi:10.1103/physrevd.84.023518

Cited by 42 publications

(56 citation statements)

References 46 publications

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“…These bounds indicate a good agreement with the forecast of Planck and CMBPol experiments [33] as well as with the upper bound provided by the constraints on the variation in the fine structure constant [35]. As we have already mentioned, the presence of dark energy at BBN era should not disturb the observed Helium abundance in the universe which is regarded as one of the major evidence in supporting the big bang theory.…”

Section: Discussionsupporting

confidence: 73%

Modified holographic Ricci dark energy coupled to interacting dark matter and a non-interacting baryonic component

2013

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We examine a Friedmann-Robertson-Walker universe filled with interacting dark matter, modified holographic Ricci dark energy (MHRDE), and a decoupled baryonic component.The estimations of the cosmic parameters with Hubble data lead to an age of the universe of 13.17 Gyr and show that the MHRDE is free from the cosmic-age problem at low redshift (0 ≤ z ≤ 2) in contrast to holographic Ricci dark energy (HRDE) case. We constrain the parameters with the Union2 data set and contrast with the Hubble data. We also study the behavior of dark energy at early times by taking into account the severe bounds found at recombination era and/or at big bang nucleosynthesis. The inclusion of a non interacting baryonic matter forces that the amount of dark energy at zt ∼ O(1) changes abruptly implying that Ωx(z ≃ 1100) = 0.03, so the bounds reported by the forecast of Planck and CMBPol experiments are more favored for the MHRDE model than in the case of HRDE cutoff. For the former model, we also obtain that at high redshift the fraction of dark energy varies from 0.006 to 0.002, then the amount of Ωx at the big bang nucleosynthesis era does not disturb the observed Helium abundance in the universe provided that the bound Ωx(z ≃ 10 10 ) < 0.21 is hold.

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Section: Discussionsupporting

confidence: 73%

Modified holographic Ricci dark energy coupled to interacting dark matter and a non-interacting baryonic component

2013

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“…With these assumptions one can explicitly relate the evolution of α to that of dark energy, as in [179] whose derivation we summarize here. The evolution of α can be written ∆α…”

Section: Canonical Scalar Fieldsmentioning

confidence: 99%

“…while in [179] an independent few-percent constraint on this coupling was obtained using CMB and large-scale structure data in combination with direct measurements of the present-day Hubble parameter. We note that there is in principle an additional source term driving the evolution of the scalar field, due to a F 2 B ′ F term.…”

Section: Canonical Scalar Fieldsmentioning

confidence: 99%

The status of varying constants: a review of the physics, searches and implications

2017

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Abstract. The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incomplete-if not incorrect-and that new physics is out there, waiting to be discovered. A key task for the next generation of laboratory and astrophysical facilities is to search for, identify and ultimately characterize this new physics. Here we highlight recent developments in tests of the stability of nature's fundamental couplings, which provide a direct handle on new physics: a detection of variations will be revolutionary, but even improved null results provide competitive constraints on a range of cosmological and particle physics paradigms. A joint analysis of all currently available data shows a preference for variations of α and µ at about the two-sigma level, but inconsistencies between different sub-sets (likely due to hidden systematics) suggest that these statistical preferences need to be taken with caution. On the other hand, these measurements strongly constrain Weak Equivalence Principle violations. Plans and forecasts for forthcoming studies with facilities such as ALMA, ESPRESSO and the ELT, which should clarify these issues, are also discussed, and synergies with other probes are briefly highlighted. The goal is to show how a new generation of precision consistency tests of the standard paradigm will soon become possible.PACS numbers: 98.80.Es, 95.36.+x, 98.62.Ra,

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“…The variation of μ and α with time or scalefactor is related to the evolution of the dark energy density and the dark energy equation of state (Calabrese et al 2011;Thompson 2012). The QCD scale as a function of the scalefactor a in slow roll quintessence is examined as an example of such evolution.…”

Section: O N C L U S I O N Smentioning

confidence: 99%

“…Independently Calabrese et al (2011) for α and Thompson (2012) for μ showed that for a rolling scalar field φ in a potential V(φ) with a quintessence dark energy equation of state…”

Section: Q U I N T E S S E N C E E X a M P L E O F Qcd E Vo L U T I O Nmentioning

confidence: 99%

Fundamental constant observational bounds on the variability of the QCD scale

Thompson¹

2017

Monthly Notices of the Royal Astronomical Society

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Many physical theories beyond the Standard Model predict time variations of basic physics parameters. Direct measurement of the time variations of these parameters is very difficult or impossible to achieve. By contrast, measurements of fundamental constants are relatively easy to achieve, both in the laboratory and by astronomical spectra of atoms and molecules in the early universe. In this work, measurements of the proton to electron mass ratio μ and the fine structure constant α are combined to place mildly model-dependent limits on the fractional variation of the quantum chromodynamic scale and the sum of the fractional variations of the Higgs vacuum expectation value (VEV) and the Yukawa couplings on time-scales of more than half the age of the universe. The addition of another model parameter allows the fractional variation of the Higgs VEV and the Yukawa couplings to be computed separately. Limits on their variation are found at the level of less than 5 × 10 −5 over the past 7 Gyr. A model-dependent relation between the expected fractional variation of α relative to μ tightens the limits to 10 −7 over the same time span. Limits on the present day rate of change of the constants and parameters are then calculated using slow roll quintessence. A primary result of this work is that studies of the dimensionless fundamental constants such as α and μ, whose values depend on the values of the physics parameters, are excellent monitors of the limits on the time variation of these parameters.

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Constraining variations in the fine structure constant in the presence of early dark energy

Cited by 42 publications

References 46 publications

Modified holographic Ricci dark energy coupled to interacting dark matter and a non-interacting baryonic component

Modified holographic Ricci dark energy coupled to interacting dark matter and a non-interacting baryonic component

The status of varying constants: a review of the physics, searches and implications

Fundamental constant observational bounds on the variability of the QCD scale

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