Quintessence and Inflation from Symmetry Breaking Transition of the Internal Manifold

Abstract

We show that even in the simple framework of pure Kaluza-Klein gravity the shape moduli can generate potentials supporting inflation and/or quintessence. Using the shape moduli as the inflaton or quintessence-field has the additional benefit of being able to explain symmetry breaking in a natural geometric way. A numerical analysis suggests that in these models it may be possible to obtain sufficient e-foldings during inflation as well as a small cosmological constant at the current epoch (without fine tuning), while preserving the constraint coming from the fine structure constant.

28 pages, 2 figures. Expanded version, essentially combining previous version with gr-qc/0305087