SEMINARIO DE FISICA TEORICA I Y II

Titulo:         Peering beyond the horizon: axion cosmology revisited 
Conferenciante: Ann Nelson (University of Washington, Seattle)
Dia y hora:     14, 14:15 (aula 8B )

Resumen:

A cosmological abundance of axions with   decay constant
above 10^{12} GeV  would be  of profound significance:   explaining the
smallness of the neutron electric dipole moment and the nature of dark
matter,  implying a fine tuning of the initial axion field value that
would strongly favor an anthropic solution  in the context of inflation 
to the dark matter abundance, and providing  circumstantial evidence for
string theory.
In this talk I discuss how    in such a scenario, constraints on the 
dipole anisotropy in the dark matter to entropy ratio places a strong
lower bound on the amount of inflation, and constraints on isocurvature
primordial perturbations place a constraint on the reheat temperature
after inflation. These conclusions apply not only to axions but to any
very light, weakly coupled scalar field, such as a string modulus.