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Further evidence for a variable fine-structure constant from Keck/HIRES QSO absorption spectra
We have previously presented evidence for a varying fine-str ucture constant, α, in two independent samples of Keck/HIRES QSO absorption spectra. Here we present a detailed manymultiplet analysis ofExpand
Further evidence for cosmological evolution of the fine structure constant.
The results of a search for time variability of the fine structure constant alpha using absorption systems in the spectra of distant quasars find no systematic effects which can explain the results. Expand
An order of magnitude sensitivity gain is described for using quasar spectra to investigate possible time or space variation in the fine structure constant $\ensuremath{\alpha}$. Applied to a sampleExpand
Indications of a spatial variation of the fine structure constant.
New Very Large Telescope (VLT) data shows an inverse evolution; α increases at high redshift; the combined data set fits a spatial dipole, significant at the 4.2 σ level. Expand
Limit on the cosmological variation of mp/me from the inversion spectrum of ammonia.
We obtain the limit on the space-time variation of the ratio of the proton mass to the electron mass, mu=m(p)/m(e), based on comparison of quasar absorption spectra of NH3 with CO, HCO+ and HCNExpand
New limits on coupling of fundamental constants to gravity using 87Sr optical lattice clocks.
The 1S0-3P0 clock transition frequency nuSr in neutral 87Sr has been measured relative to the Cs standard by three independent laboratories in Boulder, Paris, and Tokyo over the last three years. TheExpand
Further constraints on variation of the fine‐structure constant from alkali‐doublet QSO absorption lines
Comparison of quasar (QSO) absorption-line spectra with laboratory spectra provides a precise probe for variability of the fine-structure constant, α, over cosmological time-scales. We constrainExpand
Strong Limit on a Variable Proton-to-Electron Mass Ratio from Molecules in the Distant Universe
Comparing the available ammonia spectra observed toward the quasar B0218+357 with new, high-quality rotational spectra, this work presents the first detailed measurement of μ with this technique, limiting relative deviations from the laboratory value to |Δμ/μ| < 1.8 × 10–6 (95% confidence level). Expand
Possible evidence for a variable fine structure constant from QSO absorption lines: Motivations, analysis and results
An experimental search for variation in the fundamental coupling constants is strongly motivated by modern high-energy physics theories. Comparison of quasar absorption line spectra with laboratoryExpand
The density, the cosmic microwave background, and the proton-to-electron mass ratio in a cloud at redshift 0.9
Based on measurements with the Effelsberg 100-m telescope, a multi-line study of molecular species is presented toward the gravitational lens system PKS 1830-211, which is by far the best knownExpand