K-essence scalar field as dynamical dark energy
  We study an early dark energy (EDE) model as a K-essence scalar field in the framework of FLRW universe using an effective parametrization of the state equation as a function of the redshift $z$ with the tracker condition during radiation domination, but also demanding an accelerated expansion of the universe at late times emulating cosmological constant. We found all the dynamical variables of the EDE system. We use the luminosity distances of the SNIA to get the best estimations for the free parameters of the model and also, we constrain the model using primordial abundances of light nuclei in BBN theory. We summarize the necessary conditions to achieve BBN predictions and the accelerated expansion of the universe at late times. 
L. Garc\'ia, J. Tejeiro, L. Casta\~neda
astro-ph.CO