Time variation of the fine structure constant in the early universe and the Bekenstein model

MERCEDES E. MOSQUERA; CLAUDIA G. SCOCCOLA; SUSANA J. LANDAU; HECTOR VUCETICH

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES

Lugar: Paris; Año: 2008 vol. 478 p. 675 - 684

0004-6361

We calculate the bounds on the variation in the finestructure constant at the time of primordial nucleosynthesis and atthe time of neutral hydrogen formation. We used these bounds and otherbounds from the late universe to test the Bekenstein model. We modifiedthe Kawano code, CAMB, and CosmoMC to include the possiblevariation in the fine structure constant.  We used observationalprimordial abundances of $De$, $He$, and $Li$, recent datafrom the cosmic microwave background, and the 2dFGRS power spectrum, toobtain bounds on the variation in $alpha$. We calculated a piecewisesolution to the scalar field equation of the Bekenstein model in twodifferent regimes: i) matter and radiation, ii) matter andcosmological constant. We match both solutions with the appropriate boundaryconditions. We performed a statistical analysis, using the boundsobtained from the early universe and other bounds from the lateuniverse to constrain the free parameters of the model. Results areconsistent with no variation in $alpha$ for the early universe. Limitson $alpha$ are inconsistent with the scale length of the theory $l$being larger than the Planck scale. In order to fit all observationaland experimental data, the assumption $l>L_p$ implied in Bekenstein´smodel has to be relaxed.