Related papers: Inflation from a Tachyon Fluid?
We investigate the initial conditions of inflation in a Bianchi~I universe that is homogeneous but not isotropic. We use the Eisenhart lift to describe such a theory geometrically as geodesics on a field space manifold. We construct the…
We constrain several models in Tachyonic Inflation derived from the large-$N$ formalism by considering theoretical aspects as well as the latest observational data. On the theoretical side, we assess the field range of our models by means…
We investigate the universe evolution from inflation to late-time acceleration in a unified way, using a two-component fluid constituted from extended Chaplygin gas alongside a phantom scalar field. We extract solutions for the various…
The homogeneous cosmological model in GR is proposed, where the vacuum energy, which can cause the inflation, is described by tensor field rather than by commonly used in inflationary scenarios scalar field. It is shown that if the initial…
Variation of constants in the very early universe can generate inflation. We consider a scenario where the strong coupling constant was changing in time and where the gluon condensate underwent a phase transition ending the inflation.
In this paper we consider inflation as a probe of new physics near the string or Planck scale. We discuss how new physics can be captured by the choice of vacuum, and how this leads to modifications of the primordial spectrum as well as the…
I review the theory of preheating after inflation, focusing on the recently found tachyonic preheating in the theories with spontaneous symmetry breaking. This occurs due to the tachyonic instability of the scalar field near the top of its…
We perform a semi-classical analysis of the Emergent Universe scenario for inflation. Fixing the background, and taking the inflaton to be homogenous, we cast the inflaton's evolution as a one-dimensional quantum mechanics problem. We find…
Out-of-equilibrium, non-perturbative, quantum effects significantly modify the standard picture of inflation in a wide class of models including new, natural, and hybrid inflation. We find that the quantum evolution of a single real…
Inflation is nowadays a well-established paradigm consistent with all the observations. The precise nature of the inflaton is however unknown and its role could be played by any candidate able to imitate a scalar condensate in the slow-roll…
We consider a universe with a bulk viscous cosmic fluid, in a flat Friedmann-Lemaitre-Robertson-Walker geometry. We derive the conditions for the existence of inflation, and those which at the same time prevent the occurrence of…
Following recent studies of Ford, we suggest -- in the framework of general relativity -- an inflationary cosmological model with the self-interacting spinning matter. A generalization of the standard fluid model is discussed and estimates…
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 consider the brane gas picture of the early universe. At later stages, when there are no winding modes and the background is free to expand, we show that a moving 3-brane, which we identify with our universe, can inflate even though it…
We consider tachyonic warm-inflationary models in the context of intermediate inflation. We derive the characteristics of this model in slow-roll approximation and develop our model in two cases, 1- For a constant dissipative parameter…
We consider a cosmological scenario within the KKLT framework for moduli stabilization in string theory. The universal open string tachyon of decaying non-BPS D-brane configurations is proposed to drive eternal topological inflation.…
After a brief summary of general relativity and cosmology, we present the basic concepts underlying inflation, the currently best motivated models for the early Universe. We describe the simplest inflation models, based on a single scalar…
I study the post-inflation oscillation and decay of light coherent scalar field condensates that may develop during an inflationary phase of the universe. In particular, the light scalars studied are a composition of the scalar particles of…
We investigate inflation driven by the evolution of highly excited quantum states within the framework of out of equilibrium field dynamics. The self-consistent evolution of these quantum states and the scale factor is studied analytically…
In the primordial universe, fields with mass much larger than the mass-scale of the event-horizon (such as the Hubble parameter in inflation) exist ubiquitously, and can be excited from time to time and oscillate quickly around their…