Related papers: Fine structure constant measurements in quasar abs…
Searching for space-time variations of the constants of Nature is a promising way to search for new physics beyond General Relativity and the standard model motivated by unification theories and models of dark matter and dark energy. We…
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 remarkable detection of a spatial variation in the fine-structure constant, alpha, from quasar absorption systems must be independently confirmed by complementary searches. In this letter, we discuss how terrestrial measurements of…
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…
Previous, large samples of quasar absorption spectra have indicated some evidence for relative variations in the fine-structure constant ($\Delta\alpha/\alpha$) across the sky. However, they were likely affected by long-range distortions of…
Cosmography is a model-independent phenomenological approach to observational cosmology, relying on Taylor series expansions of physical quantities as a function of the cosmological redshift or other analogous variables. A recent work…
We report unbiased AI measurements of the fine structure constant $\alpha$ in two proximate absorption regions in the spectrum of the quasar HE0515$-$4414. The data are high resolution, high signal to noise, and laser frequency comb…
In the second paper of this series we extend our Bayesian reanalysis of the evidence for a cosmic variation of the fine structure constant to the semi-parametric modelling regime. By adopting a mixture of Dirichlet processes prior for the…
Searches for variations of fundamental constants require a comprehensive understanding of measurement errors. This paper examines a source of error that is usually overlooked: the impact of continuum placement error. We investigate the…
We analyse the constraints obtained from new atomic clock data on the possible time variation of the fine structure `constant' and the electron-proton mass ratio and show how they are strengthened when the seasonal variation of Sun's…
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…
Hot white dwarf stars are the ideal probe for a relationship between the fine-structure constant and strong gravitational fields, providing us with an opportunity for a direct observational test. We study a sample of hot white dwarf stars,…
Recent advances in spectroscopic instrumentation and calibration methods dramatically improve the quality of quasar spectra. Supercomputer calculations show that, at high spectral resolution, procedures used in some previous analyses of…
The Cosmic Background Radiation gives us one of the few probes into the density perturbations in the early universe that should later lead to the formation of structure we now observe. Recent advances in degree scale anisotropy measurements…
We present exact kinematic consistency relations for cosmological structures that do not vanish at equal times and can thus be measured in surveys. These rely on cross-correlations between the density and velocity, or momentum, fields.…
Recent measurements of a peak in the angular power spectrum of the cosmic microwave background appear to suggest that geometry of the universe is close to being flat. But if other accepted indicators of cosmological parameters are also…
Weak equivalence principle (WEP) is, for the first time, tested by astrometry on quasars in the sky measured in two wavelengths. Compared to previous WEP tests based on the Shapiro time delay of massless particles, this one has profound…
We assess the cosmological variability of the fine-structure constant from the analysis of an ensemble of Fe II absorption lines at the redshift z=1.15 toward the QSO HE 0515-4414 by means of the standard many-multiplet (MM) technique and…
We examine the variation of the fine structure constant in the context of a two-field quintessence model. We find that, for solutions that lead to a transient late period of accelerated expansion, it is possible to fit the data arising from…
A phenomenological model is proposed to explain the recent observed cosmological variation of the fine structure constant as an effect of the quantum vacuum, assuming a flat universe with cosmological constant $\Lambda$ in the cases…