Related papers: Primordial nucleosynthesis with a varying fine str…
The theory of Big Bang nucleosynthesis, coupled with an estimate of the primordial deuterium abundance (D/H)_pr, offers insights into the baryon density of the Universe. Independently, the baryon density can be constrained during a…
Astronomical observations have a unique ability to determine the laws of physics at distant times in the universe. They, therefore, have particular relevance in answering the basic question as to whether the laws of physics are invariant…
We calculate the dependence of atomic transition frequencies on the fine structure constant, $\alpha = e^2/\hbar c$, for some ions of Ti, Mn, Na, C, and O. The results of these calculations will be used in the search for variation of alpha…
Theories unifying gravity and other interactions suggest the possibility of spatial and temporal variation of physical ``constants'' in the Universe. Detection of high redshift absorption systems intersecting the sight lines towards distant…
We describe the changes to the standard primordial black hole constraints on density perturbations if there are modifications to the standard cosmology between the time of formation and nucleosynthesis.
We review the Cosmology and Physics underlying Primordial Nucleosynthesis and survey current observational data in order to compare the predictions of Big Bang Nucleosynthesis with the inferred primordial abundances. From this comparison we…
The observation of space-time variations in fundamental constants would provide strong evidence for the existence of new light degrees of freedom in the theory of Nature. Robustly constraining such scenarios requires exploiting observations…
The relative effects of variation of the fine structure constant alpha=e^2/hc and dimensionless strong interaction parameter m_q/Lambda_{QCD} are enhanced 5-6 orders of magnitude in very narrow ultraviolet transition between the ground and…
We study the evolution of the fine-structure constant, $\alpha$, induced by non-linear density perturbations in the context of the simplest class of quintessence models with a non-minimal coupling to the electromagnetic field, in which the…
Theories unifying gravity with other interactions suggest spatial and temporal variation of fundamental "constants" in the Universe. A change in the fine structure constant, alpha, could be detected via shifts in the frequencies of atomic…
We study the cosmological constraints of the time variation of the electron mass $m_e$ and the fine-structure constant $\alpha$, using data of cosmic microwave background, supernovae light curve and baryon acoustic oscillation (BAO) data…
Recent cosmological observations, such as the measurement of the primordial 4He abundance, CMB, and large scale structure, give preference to the existence of extra radiation component, Delta N_nu > 0. The extra radiation may be accounted…
The recent determination of the baryon-to-photon ratio from WMAP data by Spergel et al. (2003) allows one to fix with unprecedented precision the primordial abundances of the light elements D, 3He, 4He and 7Li in the framework of the…
We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place…
We determine the influence of a variation of the fundamental ``constants'' on the predicted helium abundance in Big Bang Nucleosynthesis. The analytic estimate is performed in two parts: the first step determines the dependence of the…
We study dependence of the CMB temperature anisotropy spectrum on the value of the fine structure constant $\alpha$ and the equation of state of the dark energy component of the total density of the universe. We find that bounds imposed on…
We derive here a robust bound on the effective number of neutrinos from constraints on primordial nucleosynthesis yields of deuterium and helium. In particular, our results are based on very weak assumptions on the astrophysical…
This paper presents the constraints on the time variation of the fine structure constant at recombination relative to its present value, Delta_alpha = (alpha_rec-alpha_0) / alpha_0, obtained from the analysis of the WMAP-3yr Cosmic…
In extensions of general relativity and in theories aiming at unifying gravity with the forces of the Standard Model, the value of the "fundamental constants" is often determined by the vacuum expectation value of new fields, which may thus…
We work with a class of scalar extended theory of gravity that can drive the present cosmic acceleration as well as accommodate a mild cosmic variation of the fine structure constant $\alpha$. The motivation comes from a vintage theory…