منابع مشابه
Extra Dimensions and Varying Alpha
I review recent constraints on and claimed detections of a time-varying fine-structure constant α. Our results are consistent with no variation in α 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 α and other cosmologi...
متن کاملNew Constraints on Varying Alpha
I briefly present some current theoretical motivations for time or space variations of the fundamental constants of nature and review current key observational results. I focus on the fine-structure constant, and particularly on measurements using quasars and the cosmic microwave background. I also compare various observational results to the simplest model-building expectations .
متن کاملQualitative Analysis of Universes with Varying Alpha
Assuming a Friedmann universe which evolves with a power-law scale factor, a = tn, we analyse the phase space of the system of equations that describes a time-varying fine structure ’constant’, α, in the Bekenstein-Sandvik-Barrow-Magueijo generalisation of general relativity. We have classified all the possible behaviours of α(t) in ever-expanding universes with different n and find new exact s...
متن کاملGauge-Invariant Perturbations of Varying-Alpha Cosmologies
Using a gauge-invariant formalism we derive and solve the perturbed cosmological equations for the BSBM theory of varying fine structure ’constant’. We calculate the time evolution of inhomogeneous perturbations of the fine structure constant, δα α on small and large scales with respect to the Hubble radius. In a radiationdominated universe small inhomogeneities in α will decrease on large scal...
متن کاملObservational Constraints on Varying-Alpha Domain Walls
We consider the possibility that current hints of spatial variations of the fine structure constant at high redshift, based on VLT/UVES and Keck/HIRES observations, could be caused by a biased domain wall network described by a scalar field non-minimally coupled to the electromagnetic field. We show that in order to be responsible for the reported spatial variations of the fine structure consta...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Annalen der Physik
سال: 2010
ISSN: 0003-3804
DOI: 10.1002/andp.201010416