Mutated hilltop inflation revisited

Abstract

In this work we re-investigate pros and cons of mutated hilltop inflation. Applying Hamilton-Jacobi formalism we solve inflationary dynamics and find that inflation goes on along the ${\mathcal{W}}_{-1}$ branch of the Lambert function. Depending on the model parameter mutated hilltop model renders two types of inflationary solutions: one corresponds to small inflaton excursion during observable inflation and the other describes large field inflation. The inflationary observables from curvature perturbation are in tune with the current data for a wide range of the model parameter. The small field branch predicts negligible amount of tensor to scalar ratio $r\sim \mathcal{O}(10^{-4})$, while the large field sector is capable of generating high amplitude for tensor perturbations, $r\sim \mathcal{O}(10^{-1})$. Also, the spectral index is almost independent of the model parameter along with a very small negative amount of scalar running. Finally we find that the mutated hilltop inflation closely resembles the $\alpha$-attractor class of inflationary models in the limit of $\alpha \varphi \gg 1$.

17 pages, 13 figures. Accepted for publication in EPJC

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• More hilltop inflation models
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• LiteBIRD and CMB-S4 Sensitivities to Reheating in Plateau Models of Inflation
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• Realising Mutated Hilltop Inflation in Supergravity
• An Inflationary Equation of State
• Returning Back to Mukhanov Parametrization of Inflationary Equation of State
• Inflationary models in a minimally coupled $f(R,T)$ gravity: Constraints from $Planck$, BICEP/$Keck$, and ACT
• Mutated hilltop inflation in light of Planck/ACT observations