Related papers: Initial conditions for small-field inflation
We investigate a nonsingular initial state of the Universe which leads to inflation naturally. The model is described by a scalar field with a quadratic potential in Eddington-inspired Born-Infeld gravity. The curvature of this initial…
We perform a numerical investigation of the field evolution in the smooth hybrid inflationary model. We find that for almost all the examined initial values we do get an adequate amount of inflation. Our results show that the model is…
Multiple axions form a landscape in the presence of various shift symmetry breaking terms. Eternal inflation populates the axion landscape, continuously creating new universes by bubble nucleation. Slow-roll inflation takes place after the…
Slow-roll inflation requires the inflaton field to have an exceptionally flat potential, which combined with measurements of the scale of inflation demands some degree of fine-tuning. Alternatively, the flatness of the potential could be…
Models of cosmic inflation suggest that our universe underwent an early phase of accelerated expansion, driven by the dynamics of one or more scalar fields. Inflationary models make specific, quantitative predictions for several observable…
The inflationary scenario, which states that the early universe underwent a brief but dramatic period of accelerated spatial expansion, has become the current paradigm of early universe cosmology. Although inflationary cosmology has its…
We determine the frequency of regions of small-field inflation in the Wigner landscape as an approximation to random supergravities/type IIB flux compactifications. We show that small-field inflation occurs exponentially more often than…
We study inflationary potentials in the framework of superstring theories. Successful inflation may occur due to chiral fields, but only after the dilaton and moduli are stabilized. This is achieved by demanding an S-duality invariant…
Inflation can occur in the cores of topological defects, where the scalar field is forced to stay near the maximum of its potential. This topological inflation does not require fine-tuning of the initial conditions.
In this short note we discuss the possibility of producing a slow rolling inflationary background by considering a massive scalar field whose kinetic term is non-minimally coupled to gravity.
Multifield models of inflation with nonminimal couplings are in excellent agreement with the recent results from {\it Planck}. Across a broad range of couplings and initial conditions, such models evolve along an effectively single-field…
Some recent studies based on numerical relativity simulations claim that slow contraction/ekpyrosis is strongly preferred over inflation as the smoothing mechanism that brought the universe into the homogeneous, isotropic and flat state we…
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 various inflation models in the context of the no-boundary proposal. We propose that a good inflation model should satisfy three conditions: observational constraints, plausible initial conditions, and…
We consider the behaviour of a quintessence field during an inflationary epoch, in order to learn how inflation influences the likely initial conditions for quintessence. We use the stochastic inflation formalism to study quantum…
In hybrid inflation, initial field values leading to sufficiently long inflation were thought be fine-tuned in a narrow band along the inflationary valley. A re-analysis of this problem has shown that there exists a non negligible…
We discuss the initial conditions problem for inflation driven by the vacuum energy of a plateau potential, and in particular the Starobinsky inflation. We show that the supergravity embedding of the $R+R^2$ theory naturally decreases the…
We study the conditions needed to have an early epoch of inflationary expansion with a potential coming from IIB superstring theory with fluxes involving two moduli fields. The phenomenology of this potential is different from the usual…
An early stage of kinetic energy domination for inflation is applied to single-field quadratic and hybrid-type potentials considering only the amount of inflation necessary to solve the problems of the standard cosmological scenario. Using…
An attractive candidate for the inflaton is an axion slowly rolling down a flat potential protected by a perturbative shift symmetry. Realisations of this idea within large field, natural and monomial inflation have been disfavoured by…