A Double-Sine-Gordon Early Universe

A solitonic model of the early universe is introduced by employing the Double-Sine-Gordon (DSG) potential. The model predicts the appropriate number of e-foldings ($N_e$) required for favored inflation and is an advantage for the model in addressing the flatness, horizon, and magnetic monopole problems. Compatibility of the model with observations, including the Planck $2018$ data \cite{Akrami et al. (2020)} and the Planck $2018$ data+BK$18$+BAO \cite{Ade et al. (2021)} paves the way to estimate the model's free parameters. The results generate acceptable and proper values for the spectral index ($n_s$) and the tensor-to-scalar ratio ($r$) in agreement with the Planck $2018$ data \cite{Akrami et al. (2020)} and the Planck $2018$ data+BK$18$+BAO \cite{Ade et al. (2021)}. Correspondingly, a consistent description of the reheating era is obtained, yielding positive reheating number of e-foldings ($N_{\mathrm{reh}}$) and reheating final temperature ($T_{\mathrm{reh}}$) from $10^{-2}$ GeV to $10^{16}$ GeV. Overall, the model seems viable at the inflationary and reheating eras.