Related papers: Possible time-variability of the fine-structure co…
A new method for examining the possible space-time variation of the fine structure constant ($\alpha$) is proposed. The technique uses a relatively simple measurement with an optical resonator to compare atom-stabilized optical frequency…
There has been some evidence that the fine structure "constant" $\alpha$ may vary with time. We point out that this variation can be described by a scalar field in some supergravity theory in our toy model, for instance, the N=8 extended…
A variation of fundamental constants of physics is proposed in a frame of static universe. It is shown when the velocity of light increases (decreases) the Planck's constant increases (decreases) and mass of bodies decreases (increases).…
The gravitational field produced by a domain wall acts as a medium with spacetime-dependent permittivity \epsilon. Therefore, the fine structure constant \alpha = e^2/4 \pi \epsilon will be a time-dependent function at fixed position. The…
We discuss present and future cosmological constraints on variations of the fine structure constant $\alpha$ induced by an early dark energy component having the simplest allowed (linear) coupling to electromagnetism. We find that current…
We discuss the fundamemtal constants in the Standard Model of particle physics, in particular possible changes of these constants on the cosmological time scale. The Grand Unification of the observed strong, electromagnetic and weak…
Asymptotically safe quantum fluctuations of gravity can uniquely determine the value of the gauge coupling for a large class of grand unified models. In turn, this makes the electromagnetic fine-structure constant calculable. The balance of…
An alternative to dark energy as an explanation for the present phase of accelerated expansion of the Universe is that the Friedmann equation is modified, e.g. by extra dimensional gravity, on large scales. We explore a natural…
We consider a cosmological model with a variable gravitational constant, G, based on a scalar-tensor theory. Using the recent observational data for the Hubble diagram of type Ia supernovae (SNeIa) we find a phenomenological expression…
We propose to generalize Bekenstein model for the time variation of the fine structure "constant" $\alpha_{em}$ to QCD strong coupling constant $\alpha_S$. We find that, except for a ``fine tuned'' choice of the free parameters, the…
Recent observations of the fine structure of spectral lines in the early universe have been interpreted as a variation of the fine structure constant. From the assumed validity of Maxwell equations in general relativity and well known…
If our Universe is allowed to absorb baby universes, one obtains a modified Friedmann equation that can explain the late time acceleration of our Universe and there is no need for a cosmological constant. In addition the modified Friedmann…
We study the time variation of fundamental constants in the early Universe. Using data from primordial light nuclei abundances, CMB and the 2dFGRS power spectrum, we put constraints on the time variation of the fine structure constant…
When dark matter structures form and equilibrate they have to release a significant amount of energy in order to obey the virial theorem. Since dark matter is believed to be unable to radiate, this implies that some of the accreted dark…
We report new upper limits on any possible long-term time variation of the ratio of the electron to proton masses, $(m_e/m_p)$, the fine-structure constant, ($\alpha$), and the quantity $\alpha^2 g_p(m_e/m_p)$, where $g_p$ is the proton…
The optical spectra of objects classified as QSOs in the SDSS DR6 are analyzed with the aim of determining the value of the fine structure constant in the past and then check for possible changes in the constant over cosmological…
The framework for considering the astronomical and cosmological observations in the context of scalar-tensor quintessence in which the quintessence field also accounts for a time dependence of the gravitational constant is developed. The…
Attempts to measure the variability of the fine structure constant alpha over cosmological time, using spectra of high redshift quasars have produced conflicting results. We use the Many Multiplet (MM) method with Mg II and Fe II lines on…
Recent discussions suggest the possibility that short distance physics can significantly modify the behavior of quantum fluctuations in the inflationary universe, and alter the standard large scale structure predictions. Such modifications…
In this review we discuss the progress of the past decade in testing for a possible temporal variation of the fine structure constant $\alpha$. Advances in atomic sample preparation, laser spectroscopy and optical frequency measurements led…