Related papers: Spatial variation in the fine-structure constant -…
Most of the successful physical theories rely on the constancy of few fundamental quantities (such as the speed of light, $c$, the fine-structure constant, \alpha, the proton to electron mass ratio, \mu, etc), and constraining the possible…
There are indications from the study of quasar absorption spectra that the fine structure constant $\alpha$ may have been measurably smaller for redshifts $z>2.$ Analyses of other data ($^{149}$Sm fission rate for the Oklo natural reactor,…
Recent quasar spectroscopy from the VLT and Keck telescopes suggests that fundamental constants may not actually be constant. To better confirm or refute this result, systematic errors between telescopes must be minimized. We present a new…
We study the large-scale anisotropy of the Universe by measuring the dipole in the angular distribution of a flux-limited, all-sky sample of 1.36 million quasars observed by the Wide-field Infrared Survey Explorer (WISE). This sample is…
We report a new constraint on the variation of the fine-structure constant based on the analysis of 15 Si IV doublets selected from a ESO-UVES sample. We find \Delta\alpha/\alpha = (+0.15+/-0.43) x 10^-5 over a redshift range of 1.59< z <…
We report a robust constrain on the possible variation of fine-structure constant, alpha = e^2/(hbar*c), obtained using O III 4959,5007, nebular emission lines from QSOs. We find Delta-alpha/alpha=-(2.1 +/- 1.6) x 10^(-5) based on a well…
We attempt to measure possible miscalibration of the wavelength scale of the VLT-UVES spectrograph. We take spectra of QSO HE0515-4414 through the UVES iodine cell which contains thousands of well-calibrated iodine lines and compare these…
The detection of a spatial variation of the fine-structure constant, alpha, based on study of quasar absorption systems has recently been reported. The physics that causes this alpha-variation should have other observable manifestations,…
In their Letter [Phys. Rev. Lett. 92, 121302 (2004)] (also [Astron. Astrophys. 417, 853 (2004)]), Srianand et al. analysed optical spectra of heavy-element species in 23 absorption systems along background quasar sight-lines, reporting…
This article reviews the two major recent developments that significantly improved cosmological measurements of fundamental constants derived from high resolution quasar spectroscopy. The first one is the deployment of astronomical Laser…
Some models of the expanding Universe predict that the astrometric proper motion of distant radio sources embedded in space-time are non-zero as radial distance from observer to the source grows. Systematic effects due to this proper motion…
We study a theory in which the electromagnetic field is disformally coupled to a scalar field, in addition to a usual non-minimal electromagnetic coupling. We show that disformal couplings modify the expression for the fine-structure…
Detecting or placing upper limits on spacetime variations of fundamental constants requires quantifying every potential source of uncertainty. We continue our previous study into the impact of continuum variations on measurements of the…
We review recent activity searching for variations in the fundamental constants of nature in quasar absorption spectra and in the laboratory. While research in this direction has been ongoing for many decades, the topic has recently been…
Spatial and temporal variations in the electron-to-proton mass ratio, mu, and in the fine-structure constant, alpha, are predicted in non-Standard models aimed to explain the nature of dark energy. Among them the so-called chameleon-like…
We present a large high-resolution study of the distribution and evolution of CIV absorbers, including the weakest population with equivalent widths $W_r<0.3$~{\AA}. By searching 369 high-resolution, high signal-to-noise spectra of quasars…
Recent experimental data indicates that the fine structure constant alpha may be varying on cosmological time scales. We consider the possibility that such a variation could be induced by a second order phase transition which occurs at late…
The Cosmological Principle, that the Universe is homogeneous and isotropic on sufficiently large scales, underpins the standard model of cosmology. However, a recent analysis of 1.36 million infrared-selected quasars has identified a…
Observations of the redshift z=7.085 quasar J1120+0641 have been used to search for variations of the fine structure constant, alpha, over the redshift range 5.5 to 7.1. Observations at z=7.1 probe the physics of the universe when it was…
We use, for the first time, the Detrend Fluctuation Analysis (DFA) to study the correlation properties of the transmitted flux fluctuations, in the Lyman-$\alpha$ (Ly$\alpha$) Forest along the lines of sight (LOS) to QSOs, at different…