Related papers: A Natural Inflation inspired model
A pseudo-Nambu-Goldstone boson, with a potential of the form $ V(\phi) = \Lambda^4 [1 + \cos(\phi/f)]$, can naturally give rise to an epoch of inflation in the early universe (Freese, Frieman, and Olinto 1990). The potential is naturally…
Inflationary models based on a single scalar field $\phi$ with a quadratic potential $V = \frac{1}{2} m^2 \phi^2$ are disfavoured by the recent Planck constraints on the scalar index, $n_s$, and the tensor-to-scalar ratio for cosmological…
Motivated by the idea that inflation occurs at the GUT symmetry breaking scale, in this paper we construct a new class of large field inflaton potentials where the inflaton starts with a power law potential; after initial period of relative…
Theories where the Planck scale is dynamically generated from dimensionless interactions provide predictive inflationary potentials and super-Planckian field variations. We first study the minimal single-field realisation in the low-energy…
We examine natural inflation without the use of the standard slow-roll approximation by considering the number of physical e-folds $\ln (a_eH_e/aH)$. We show that $\tilde{H} = aH \propto \cos(A \phi/2)^{2/A^2} \sin(A \phi/2)$ produces a…
We describe the general inflationary dynamics that can arise with a single, canonically coupled field where the inflaton potential is a 4-th order polynomial. This scenario yields a wide range of combinations of the empirical spectral…
A new family of inflation models is introduced and studied. The models are characterised by a scalar potential which, far from the origin, approaches an inflationary plateau in a power-law manner, while near the origin becomes monomial, as…
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…
We analyze a model of hybrid natural inflation based on the smallest non-Abelian discrete group S_3. Leading invariant terms in the scalar potential have an accidental global symmetry that is spontaneously broken, providing a…
Inflation in the framework of $f(R)$ modified gravity is revisited. We study the conditions that $f(R)$ should satisfy in order to lead to a viable inflationary model in the original form and in the Einstein frame. Based on these criteria…
In this paper we propose two simple minimal Higgs inflation scenarios through a simple modification of the Higgs potential, as opposed to the usual non-minimal Higgs-gravity coupling prescription. The modification is done in such a way that…
We present a model which contains a new complex scalar field $\Psi$, interacting with a new real scalar field, $\chi$, and an effective potential whose symmetry is almost exact, being explicitly broken by Planck-scale effects. We study the…
Inflection-point inflation is an interesting possibility to realize a successful slow-roll inflation when inflation is driven by a single scalar field with its initial value below the Planck mass ($\phi_I \lesssim M_{Pl}$). In order for a…
A new hybrid inflationary scenario in the context of $f(R,{\Box}R)$-gravity is proposed. Demanding the waterfall field to 'support the potential from below' [unlike the original proposal by Stewart in Phys. Lett. B345, 414 (1995)], we…
We consider a natural new inflationary model in broken supergravity based on an R symmetry. The model predicts a concrete relation between the amplitude of primordial density fluctuations and the scale of supersymmetry breaking. The…
We propose a class of inflation models with potential V(\phi)=\alpha \phi^n exp(-\beta^m \phi^m). We show that such kind of inflaton potentials can be realized in supergravity theory with a small shift symmetry breaking term in the K\"ahler…
We study a supergravity model of inflation essentially depending on one parameter which can be identified with the slope of the potential at the origin. In this type of models the inflaton rolls at high energy from negative values and a…
We show that the scale of the inflationary potential may be the electroweak scale or even lower, while still generating an acceptable spectrum of primordial density perturbations. Thermal effects readily lead to the initial conditions…
In this paper, we investigate models where a scalar field driving inflation is minimally coupled with gravity and it is subjected to a scalar potential. We present several examples of coupling between the field and gravity, and we furnish…
The previously proposed class of phenomenological inflationary models in which the assumption of inflaton slow-roll is replaced by the more general, constant-roll condition is compared with the most recent cosmological observational data,…