Constraining the cosmological time variation of the fine - structure constant

The variation of the fine-structure constant α = e 2 / ħ c can be probed by comparing the wavelength of atomic transitions from the redshift of quasars in the Universe and laboratory over cosmological time scales t ~ 10 10 yr. After a careful selection of pairs of lines, the Thong method with a derived analytical expression for the error analysis was applied to compute the α variation. We report a new constraint on the variation of the fine-structure constant based on the analysis of the C IV , N V , Mg II , Al III , and Si IV doublet absorption lines. The weighted mean value of the variation in α derived from our analysis over the redshift range 0.4939 ≤ z ≤ 3.7 is = ( 0.09 ± 0.07)×10 −5 . This result is three orders of magnitude better than the results obtained by earlier analysis of the same data on the constraint on Δ α / α .