Gauge-flation: Inflation From Non-Abelian Gauge Fields

Abstract

Inflationary models are usually based on dynamics of one or more scalar fields coupled to gravity. In this work we present a new class of inflationary models, gauge-flation or non-Abelian gauge field inflation, where slow-roll inflation is driven by a non-Abelian gauge field. This class of models are based on a gauge field theory with a generic non-Abelian gauge group minimally coupled to gravity. We then focus on a particular gauge-flation model by specifying the action for the gauge theory which allows for a successful slow-roll inflation. This model has two parameters the value of which can be fixed using the CMB and other cosmological data. These values are within the natural range of parameters in generic grand unified theories of particle physics.

Figures (2)

• Figure 1: In the left panel we have depicted ${P_{_{R}}}+{P_{_{L}}}$. In the standard scalar-driven inflationary models ${P_{_{R}}}={P_{_{L}}}=1$. The right panel the parity violating factor $\frac{P_{_{R}}-P_{_{L}}}{P_{_{R}}+P_{_{L}}}$ versus $\gamma$ for $\psi=10^{-2}$ and $\psi=0.12$ is shown. The power spectra have been calculated at $k\tau=-0.01$, long enough after modes have crossed the horizon and behave quite classically. As we see in the right panel, for very small and very large $\gamma$ values $P_{_{R}}\gg P_{_{L}}$.
• Figure 2: The left panel shows $1\sigma$ and $2\sigma$ contour bounds of 7-year WMAP+BAO+H0. The yellow area (region with lighter color) represents the gauge-flation predictions for $\psi\in(0.01,0.12)$ range. The region with enough number of e-folds restricts us to $n_s>0.98$ region, that is on the right-side of the $N_e=50$ line gauge-flation-prd. Therefore, the allowed region is the highlighted region between $N_e=50$ and $n_s=1$ lines. The shaded region in right panel shows the allowed values for $\epsilon$ and $\psi$.