Quintessence Unification Models from Non-Abelian Gauge Dynamics

Abstract

We show that the condensates of a non-abelian gauge group, unified with the standard model gauge groups, can parameterize the present day cosmological constant and play the role of quintessence. The models agree with SN1a and recent CMB analysis. These models have {\it no free} parameters. Even the initial energy density at the unification scale and at the condensation scale are fixed by the number of degrees of freedom of the gauge group (i.e. by $N_c, N_f$). The values of $N_c, N_f$ are determined by imposing gauge coupling unification and the number of models is quite limited. Using Affleck-Dine-Seiberg superpotential one obtains a scalar potential $V=\Lm_c^{4+n}\phi^{-n}$. Models with $2<n<4.27$ or equivalently $2\times 10^{-2} GeV < \Lm_c < 6 \times 10^3 GeV$ do not satisfy the unification constrain. In fact, there are only three models and they have an inverse power potential with $6/11 \leq n \leq 2/3$. Imposing primordial nucleosynthesis bounds the preferred model has $N_c=3, N_f=6$, with $n=2/3$, a condensation scale $\Lm_c=4.2\times 10^{-8} GeV$ and $\wpo=-0.90$ with an average value $\weff=-0.93$. Notice that the tracker solution is not a good approximation since it has $w_{tr}=-\fr{2}{n+2}=-0.75$ for $n=2/3$. We study the evolution of all fields from the unification scale and we calculate the relevant cosmological quantities. We also discuss the supersymmetry breaking mechanism which is relevant for these models.