MG11 
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Abstract

Early universe consequences of time-dependent large extra dimensions

Time-dependent compactification radii for ADD-style large extra dimensions are discussed in light of observational evidence suggesting a changing Newtonian gravitational constant. Astrophysical implications are considered, in particular focusing on inflationary and big bang nucleosynthesis constraints. Consequential limits on the size and number of extra dimensions are evaluated, as well on the evolution of the compactification radii.

Fractal holography: toward a geometric origin of cosmological large scale structure

The fractal dimension of large-scale galaxy clustering has been demonstrated to be roughly $D_F \sim 2$ from a wide range of redshift surveys. This statistic is of interest for two main reasons: fractal scaling is an implicit representation of information content, and also the value itself is a geometric signature of area. It is proposed that the fractal distribution of galaxies may thus be interpreted as a signature of holography (``fractal holography''), providing more support for current theories of holographic cosmologies. Implications for entropy bounds are addressed. In particular, because of spatial scale invariance in the matter distribution, it is shown that violations of the spherical entropy bound can be removed. This holographic condition instead becomes a rigid constraint on the nature of the matter density and distribution in the Universe.