Varying $α$ in the early universe: CMB, LSS and FMA

C. J. A. P. Martins

Published 2002-05-06Version 1

I review recent constraints on and claimed detections of a time-varying fine-structure constant $\alpha$, and discuss our own work, particularly on the effects of $\alpha$ in the cosmic microwave background and large-scale structure. Our results are consistent with no variation in $\alpha$ from the epoch of recombination to the present day, and restrict any such variation to be less than about 4%. The forthcoming MAP and Planck experiments will be able to break most of the currently existing degeneracies between $\alpha$ and other parameters, and measure $\alpha$ to better than percent accuracy.