A divergence free parametrization of deceleration parameter for scalar
  field dark energy
  In this paper, we have considered a spatially flat FRW universe filled with
pressureless matter and dark energy. We have considered a phenomenological
parametrization of the deceleration parameter $q(z)$ and from this we have
reconstructed the equation of state for dark energy $\omega_{\phi}(z)$. This
divergence free parametrization of the deceleration parameter is inspired from
one of the most popular parametrization of the dark energy equation of state
given by Barboza and Alcaniz. Using the combination of datasets (SN Ia $+$
Hubble $+$ BAO/CMB), we have constrained the transition redshift $z_{t}$ (at
which the universe switches from a decelerating to an accelerating phase) and
have found the best fit value of $z_{t}$. We have also compared the
reconstructed results of $q(z)$ and $\omega_{\phi}(z)$ and have found that the
results are compatible with a $\Lambda$CDM universe if we consider SN Ia $+$
Hubble data but inclusion of BAO/CMB data makes $q(z)$ and $\omega_{\phi}(z)$
incompatible with $\Lambda$CDM model. The potential term for the present toy
model is found to be functionally similar to a Higgs potential.
