Related papers: Thoughts on Tachyon Cosmology
Regarding the current status of the superstring theory, despite its fully developed contents of all interactions in nature, it is no doubt that unfortunately it lacks a well established early universe cosmology content, that is, the…
Inflationary cosmology has provided a predictive and phenomenologically very successful scenario for early universe cosmology. Attempts to implement inflation using scalar fields, however, lead to models with serious conceptual problems. I…
This is a short account, based on a talk given at the 2024 Moriond Cosmology Conference, of where and why string theory matters in early universe cosmology. It is written for a cosmology audience predisposed to be at best sceptical, and at…
These lectures present a brief review of inflationary cosmology, provide an overview of the theory of cosmological perturbations, and then focus on the conceptual problems of the current paradigm of early universe cosmology, thus motivating…
By compactifying a critical bosonic string theory on an internal non-flat space with a constant volume, we study the role played by the closed string tachyon in the cosmology of the effective four-dimensional space-time. The effective…
An overview is presented of some cosmological aspects of string theory. Recent developments are emphasised, especially the attempts to derive inflation or alternatives to inflation from the dynamics of branes in string theory. Time…
We present a cosmological landscape where the classical closed string tachyon field plays an important role in the framework of a critical bosonic compactification. Our cosmological solutions for a universe with constant curvature describes…
We consider cosmological consequences of string theory tachyon condensation. We show that it is very difficult to obtain inflation in the simplest versions of this theory. Typically, inflation in these theories could occur only at…
In spite of the phenomenological successes of the inflationary universe scenario, the current realizations of inflation making use of scalar fields lead to serious conceptual problems which are reviewed in this lecture. String theory may…
After 25 years of its existence, inflationary theory gradually becomes the standard cosmological paradigm. However, we still do not know which of the many versions of inflationary cosmology will be favored by the future observational data.…
In spite of its great phenomenological success, current models of scalar field-driven inflation suffer from important unresolved conceptual issues. New fundamental physics will be required to address these questions. String theory is a…
We study the possibility to construct an observationally viable scenario where both early Inflation and the recently detected accelerated expansion of the universe can be explained by using a single scalar field associated with the Tachyon.…
Closed string tachyon condensation in spacetime generates potentials on the worldsheet that model two-dimensional inflationary cosmology. These models illustrate and elucidate a variety of aspects of inflation, in particular the generation…
The inflationary scenario has become the paradigm of early universe cosmology, and - in conjuction with ideas from superstring theory - has led to speculations about an "inflationary multiverse". From a point of view of phenomenology, the…
In this article we study closed inflationary universe models by using a tachyonic field theory. We determine and characterize the existence of an universe with $\Omega > 1$, and which describes a period of inflation. We find that considered…
We investigate the tachyon-dilaton-metric system to study the "graceful exit" problem in string theoretic inflation, where tachyon plays the role of the scalar field. From the phase space analysis, we find that the inflationary phase does…
In certain implementations of the brane inflationary paradigm, the exit from inflation occurs when the branes annihilate through tachyon condensation. We investigate various cosmological effects produced by this tachyonic era. We find that…
We consider cosmological inflation driven by the rolling tachyon in the context of the braneworld scenario. We show that sufficient inflation consistent with the observational constraints can be achieved for well defined upper limits on the…
In the present work an inflationary tachyon field model of the early universe is considered. Several cosmological effects produced by a particular potential in this tachyonic era are studied, under the approximation of slow-roll inflation.…
In this article, our prime objective is to study the inflationary paradigm from generalized tachyon (GTachyon) living on the world volume of a non-BPS string theory. The tachyon action is considered here is getting modified compared to the…