A model for the very early Universe
Abstract
A model with N species of massless fermions interacting via (microscopic) gravitational torsion in de Sitter spacetime is investigated in the limit N->infinity. The U_V(N)*U_A(N) flavor symmetry is broken dynamically irrespective of the (positive) value of the induced four-fermion coupling. This model is equivalent to a theory with free but massive fermions fluctuating about the chiral condensate. When the fermions are integrated out in a way demonstrated long ago by Candelas and Raine, the associated gap equation together with the Friedmann equation predict that the Hubble parameter vanishes. Introducing a matter sector (subject to a finite gauge symmetry) as a source for subsequent cosmology, the neutral Goldstone field acquires mass by the chiral anomaly, resulting in a Planck-scale axion.
Keywords
Cite
@article{arxiv.0801.0197,
title = {A model for the very early Universe},
author = {Francesco Giacosa and Ralf Hofmann and Matthias Neubert},
journal= {arXiv preprint arXiv:0801.0197},
year = {2009}
}
Comments
14 pages, 2 figures; some references added; version to appear in JHEP