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Absorption-line systems detected in high resolution quasar spectra can be used to compare the value of dimensionless fundamental constants such as the fine-structure constant, alpha, and the proton-to-electron mass ratio, mu = m_p/m_e, as measured in remote regions of the Universe to their value today on Earth. In recent years, some evidence has emerged of small temporal and also spatial variations in alpha on cosmological scales which may reach a fractional level of 10 ppm . We are conducting a Large Programme of observations with VLT UVES to explore these variations. We here provide a general overview of the Large Programme and report on the first results for these two constants, discussed in detail in Molaro et al. and Rahmani et al. A stringent bound for Delta(alpha)/Alpha is obtained for the absorber at_abs = 1.6919 towards HE 2217-2818. The absorption profile is complex with several very narrow features, and is modeled with 32 velocity components. The relative variation in alpha in this system is +1.3+-2.4_{stat}+-1.0_{sys} ppm if Al II lambda 1670AA and three Fe II transitions are used, and +1.1+-2.6_{stat} ppm in a lightly different analysis with only Fe II transitions used. The expectation at this sky position of the recently-reported dipolar variation of alpha is (3.2--5.4)+-1.7 ppm depending on dipole model. This constraint of Delta(alpha)/alpha at face value is not supporting this expectation but is not inconsistent with it at the 3 sigma level. For the proton-to-electron mass ratio the analysis of the H_2 absorption lines of the z_{abs}~2.4018 damped Ly alpha system towards HE 0027- 1836 provides Delta(mu)/mu = (-7.6 +- 8.1_{stat} +- 6.3_{sys}) ppm which is also consistent with a null variation. (abridged)
We use the three-scale framework of Hu et al. to show how the Cosmic Microwave Background anisotropy spectrum depends on the fundamental constants. As expected, the spectrum depends only on emph{dimensionless} combinations of the constants, and we em
The values of the fundamental constants such as $mu = m_P/m_e$, the proton to electron mass ratio and $alpha$, the fine structure constant, are sensitive to the product $sqrt{zeta_x^2(w+1)}$ where $zeta_x$ is a coupling constant between a rolling sca
The observed constraints on the variability of the proton to electron mass ratio $mu$ and the fine structure constant $alpha$ are used to establish constraints on the variability of the Quantum Chromodynamic Scale and a combination of the Higgs Vacuu
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 with time. T
Many cosmological models invoke rolling scalar fields to account for the observed acceleration of the expansion of the universe. These theories generally include a potential V(phi) which is a function of the scalar field phi. Although V(phi) can be r