Mutated hilltop inflation revisited

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 ${\cal W}_{-1}$ 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 $\alpha\phi\gg 1$.Comment: 17 pages, 13 figures. Accepted for publication in EPJ

A semi-analytical approach to perturbations in mutated hilltop inflation

We study cosmological perturbations and observational aspects for mutated hilltop model of inflation. Employing mostly analytical treatment, we evaluate observable parameters during inflation as well as post-inflationary perturbations. This further leads to exploring observational aspects related to Cosmic Microwave Background (CMB) radiation. This semi-analytical treatment reduces complications related to numerical computation to some extent for studying the different phenomena related to CMB angular power spectrum for mutated hilltop inflation.Comment: 7 pages, 2 figures. Improved version to appear in IJMP

Mutated Hilltop Inflation : A Natural Choice for Early Universe

We propose a model of inflation with a suitable potential for a single scalar field which falls in the wide class of hilltop inflation. We derive the analytical expressions for most of the physical quantities related to inflation and show that all of them represent the true behavior as required from a model of inflation. We further subject the results to observational verification by formulating the theory of perturbations based on our model followed by an estimation for the values of those observable parameters. Our model is found to be in excellent agreement with observational data. Thus, the features related to the model leads us to infer that this type of hilltop inflation may be a natural choice for explaining the early universe.Comment: 22 pages, 7 figures, 2 tables. Matches published version in JCA

The Berry phase in inflationary cosmology

We derive an analogue of the Berry phase associated with inflationary cosmological perturbations of quantum mechanical origin by obtaining the corresponding wavefunction. We have further shown that cosmological Berry phase can be completely envisioned through the observable parameters, viz. spectral indices. Finally, physical significance of this phase is discussed from the point of view of theoretical and observational aspects with some possible consequences of this quantity in inflationary cosmology.Comment: 9 pages, Modified version to appear in Classical and Quantum Gravity. arXiv admin note: text overlap with arXiv:quant-ph/0307084 by other author

An Inflationary Equation of State

We have studied inflationary paradigm through an inflationary equation of state. With a single parameter equation of state as a function of the scalar field responsible for accelerated expansion, we find an observationally viable model satisfying all the constraints as laid down by the recent observations. The resulting model can efficiently cover a wide range of tensor-to-scalar ratio ranging from $r\sim\mathcal{O}(10^{-1})$ to $\mathcal{O}(10^{-6})$, other inflationary observables being consistent with the latest data. Nowadays ultimate eliminator between inflationary models is the tensor-to-scalar ratio, the model presented here is capable of keeping up with the future probes of tensor-to-scalar ratio at the same time having good agreement with other inflationary observables