Remarks on M Theoretic Cosmology

Abstract

I present cosmological arguments which point towards a Horava-Witten like picture of the universe, with the unification scale of order the fundamental gravitational scale. The SUSY breaking scale is determined by the dynamics of gauge fields which are weakly coupled at the fundamental scale. Bulk moduli whose potential originates at short distances are the inflatons, while bulk moduli whose potential originates from SUSY breaking are the origin of the energy density in the present era. The latter decay just before nucleosynthesis, and a consistent theory of baryogenesis requires that there be renormalizable baryon number violating interactions at the TeV scale. The dark matter is a boundary modulus, perhaps the QCD axion, and the temperature of matter radiation equality is related to the ratio between the fundamental and effective four dimensional Planck scales. The same ratio determines the amplitude of fluctuations in the microwave background.