Related papers: $\phi^2$ Inflation at its Endpoint
We study the two-phase scenario following inflation, where the initial step is preheating, accompanied by a step of perturbative reheating at which inflaton field decays transferring all of its energy to create relativistic particles, the…
By applying a particular kind of modified gravity, we study the inflation. Precisely, we extend our investigations beyond the Einstein's gravity to explore the Natural inflation model via the term $F(\phi)T$. We compute the inflation…
We investigate a form of $ f(R) = {R^{1+\delta}}/{R_c^{\delta}}$ and study the viability of the model for inflation in the Jordan and the Einstein frames. This model is further analysed by using the power spectrum indices of the inflation…
We study warm inflation in the framework of $f(\phi)T$ gravity, where $\phi$ is the inflaton and $T$ is the trace of the energy-momentum tensor. The inflaton field is assumed to roll on the natural potential and the result is analyzed in…
Within an expansion in slow-roll inflation parameters, we derive the complete second-order expressions relating the ratio of tensor to scalar density perturbations and the spectral index of the scalar spectrum. We find that ``corrections''…
For a narrow band of values of the top quark and Higgs boson masses, the Standard Model Higgs potential develops a shallow local minimum at energies of about $10^{16}$ GeV, where primordial inflation could have started in a cold metastable…
Recent measurements from the Atacama Cosmology Telescope (ACT), combined with Planck and DESI data, suggest a scalar spectral index $n_s$ higher than the Planck 2018 baseline, thereby placing conventional attractor-type inflationary models…
We study a new class of inflation model parametrized by the Hubble radius, such that $aH\propto \exp(-k\phi^n)$. These potentials are plateau-like, and reduce to the power-law potentials in the simplest case $n=2$. We investigate the range…
A new model of inflation is described. An unusual form for the inflationary potential is obtained because the inflaton corresponds to a non-trivial path in the configuration space of the two real scalar fields of the model. The model…
We study the $R^p$ inflationary model of [Muller:1989rp] for $p>2$ using the result of Ref. [Motohashi:2014tra]. After reproducing the observable quantities: the power spectral index $n_s$, its corresponding running…
We consider $R^2$ inflation in the Palatini gravity assuming the existence of scalar fields, coupled to gravity in the most general manner. These theories, in the Einstein frame, and for one scalar field $h$, share common features with $K$…
We revisit a class of simple single-field inflation models and demonstrate that they can readily produce a negligible tensor/scalar ratio $r$. Motivated by recent work suggesting the need to introduce higher order operators to stabilise…
The BICEP2 collaboration has recently released data showing that the scalar-to-tensor ratio $r$ is much larger than expected. The immediate consequence, in the context of $f(R)$ gravity, is that the Starobinsky model of inflation is ruled…
We consider Higgs inflation with an $\alpha R^2$ term. It adds a new scalar degree of freedom, which leads to a two-field model of inflation. We do a complete slow-roll analysis of the three-dimensional parameter space of the $R^2$…
In this work we introduce a new plateau-like inflationary model including a quadratic scalar potential coupled non-minimally to gravity. This potential has a dominant constant energy density at early times which can realize successful…
We examine the impact of a non-minimal coupling of the inflaton to the Ricci scalar, $\frac12 \xi R\phi^2$, on the inflationary predictions. Such a non-minimal coupling is expected to be present in the inflaton Lagrangian on fairly general…
We present an explicit cosmological model where inflation and dark energy both could arise from the dynamics of the same scalar field. We present our discussion in the framework where the inflaton field $\phi$ attains a nearly constant…
We test a model of inflation with a fast-rolling kinetic-dominated initial condition against data from Planck using Markov chain Monte Carlo parameter estimation. We test both an $m^2 \phi^2$ potential and the $R+R^2$ gravity model and…
We discuss the impact of the preheating stage in radiative corrections due to interaction of the inflaton to fermions to $\phi^4$ inflation with non-minimal coupling in Palatini formulation. In Palatini inflation with large non-minimal…
The theory of reheating of the Universe after inflation is developed. The transition from inflation to the hot Universe turns out to be strongly model-dependent and typically consists of several stages. Immediately after inflation the field…