Study of parametrized dark energy models with a general non-canonical scalar field

In this paper, we have considered various dark energy models in the framework of a non-canonical scalar field with a Lagrangian density of the form ${\cal L}(ϕ, X)=f(ϕ)X{\left(\frac{X}{M^{4}_{Pl}}\right)}^{α-1} - V(ϕ)$, which provides the standard canonical scalar field model for $α=1$ and $f(ϕ)=1$. In this particular non-canonical scalar field model, we have carried out the analysis for $α=2$. We have then obtained cosmological solutions for constant as well as variable equation of state parameter ($ω_ϕ(z)$) for dark energy. We have also performed the data analysis for three different functional forms of $ω_ϕ(z)$ by using the combination of SN Ia, BAO and CMB datasets. We have found that for all the choices of $ω_ϕ(z)$, the SN Ia $+$ CMB/BAO dataset favors the past decelerated and recent accelerated expansion phase of the universe. Furthermore, using the combined dataset, we have observed that the reconstructed results of $ω_ϕ(z)$ and $q(z)$ are almost choice independent and the resulting cosmological scenarios are in good agreement with the $Λ$CDM model (within the $1σ$ confidence contour). We have also derived the form of the potentials for each model and the resulting potentials are found to be a quartic potential for constant $ω_ϕ$ and a polynomial in $ϕ$ for variable $ω_ϕ$.

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