Gaugessence: a dark energy model with early time radiation-like equation
  of state
  In this work, we study a new quintessence model associated with non-Abelian
gauge fields, minimally coupled to Einstein gravity. This gauge theory has been
recently introduced and studied as an inflationary model, called gauge-flation.
Here, however, we are interested in the late time cosmology of the model in the
presence of matter and radiation to explain the present time accelerating
Universe. During the radiation and matter eras, the gauge field tracks
radiation and basically acts like a dark radiation sector. As we approach lower
redshifts, the dark component takes the form of a dark energy source which
eventually becomes the dominate part of the energy budget of the Universe. Due
to the tracking feature of our model, solutions with different initial values
are attracted to a common trajectory. The existence of early dark radiation is
a robust prediction of our model which contributes to the effective number of
relativistic species, $N_{\rm eff}$ and has its own interesting observational
features.
