Inflaton versus Curvaton in Higher Dimensional Gauge Theories

Abstract

We construct a model of cosmological inflation and perturbation based on the higher-dimensional gauge theory. The inflaton and curvaton are the scalar fields arising from the extra space components of the gauge field living in more than four dimensions. We take the six-dimensional (6D) Yang-Mills theory compactified on $T^2$ as a toy model, and apply the one-loop effective potential of the inflaton and the curvaton to the curvaton scenario. We have found that the curvaton is subdominant for the linear curvature perturbation, but that a significant non-Gaussianity and a sizable tensor to scalar ratio are generated.

17 pages, 14 eps figures, The discussions of the role of the non-zero KK modes, the reheating temperature, the tensor-scalar ratio and the role of gravity added, References added, Minor changes in each sections