Jean-Philippe Uzan

Abstract: This article describes the various experimental bounds on the variation of the fundamental constants of nature. After a discussion of the role of fundamental constants, their definition and link with metrology, it reviews the various constraints on the variation of the fine-structure constant, the gravitational, weak- and strong-interaction couplings and the electron-to-proton mass ratio. The review aims (1) to provide the basics of each measurement, (2) to show as clearly as possible why it constrains a given constant, and (3) to point out the underlying hypotheses. Such an investigation is of importance in comparing the different results and in understanding the recent claims of the detection of a variation of the fine-structure constant and of the electron-to-proton mass ratio in quasar absorption spectra. The theoretical models leading to the prediction of such variation are also reviewed, including Kaluza-Klein theories, string theories, and other alternative theories. Cosmological implications of these results are also discussed. The links with the tests of general relativity are emphasized.

TL;DR: In this article, the authors studied the existence and stability of cosmological scaling solutions of a nonminimally coupled scalar field evolving in either an exponential or inverse power law potential.

TL;DR: In this paper, it was shown that this implies a limit to the number of e-foldings that could have taken place in the inflationary epoch; however this limit is consistent with some inflationary models that solve all the usual cosmological problems and are consistent with standard structure formation theory.

TL;DR: In this paper, the signature of the seventeen multiconnected flat spaces in cosmic microwave background (CMB) maps was investigated, and it was shown that the correlated circles on a CMB map are generically not back to back, so that negative search of back-to-back circles in the Wilkinson Microwave Anisotropy Probe data does not exclude a vast majority of flat or nearly flat spaces.

TL;DR: In this paper, the authors show that existing observational constraints imply that the reciprocity relation cannot be violated by more than 0.01% between decoupling and today, and compare this effect to other sources of violation of the distance-duality relations which induce spectral distortion of the cosmic microwave background spectrum.