Related papers: Tachyon Condensates and String Theoretic Inflation
An important unsolved problem that affects practically all attempts to connect string theory to cosmology and phenomenology is how to distinguish effective field theories belonging to the string landscape from those that are not consistent…
Dirac-Born-Infeld type effective actions reproduce many aspects of string theory classical tachyon dynamics of unstable Dp-branes. The inhomogeneous tachyon field rolling from the top of its potential forms topological defects of lower…
It has been shown recently that the background independent open string field theory provides an exact description of the tachyon condensation on unstable D-branes of bosonic string theory. In this analysis the overall normalisation of the…
In the present work, we study warm tachyon inflation model in the context of "logamediate inflation" where the cosmological scale factor expands as $a=a_0\exp(A[\ln t]^{\lambda})$. The characteristics of this model in slow-roll…
We present a new class of solution to the ten-dimensional type 0 effective action. Given a generic potential of tachyon field, there exist phases where tachyon is either frozen at local extremals or free to propagate along flat directions.…
We discuss inflation models within supersymmetry and supergravity frameworks with a landscape of chiral superfields and one $U(1)$ shift symmetry which is broken by non-perturbative symmetry breaking terms in the superpotential. We label…
We study soliton solutions in scalar field theory with a variety of unbounded potentials. A subset of these potentials have Gaussian lump solutions and their fluctuation spectrum is governed by the harmonic oscillator problem. These lumps…
We present a field theory solution to the eta problem. By making the inflaton field the phase of a baryon of SU(N_c) supersymmetric Yang-Mills theory we show that all operators that usually spoil the flatness of the inflationary potential…
We investigate spectrum of open strings on D-branes after tachyon condensation in bosonic string theory. We calculate 1-loop partition function of the string and show that its limiting forms coincide with partition functions of open strings…
This paper represents an in-depth treatment of the chain inflation scenario. We fully determine the evolution of the universe in the model, the necessary conditions in order to have a successful inflationary period, and the matching with…
We obtain cosmological constraints on models of inflation which exhibit rapid roll solutions. Rapid roll attractors exist for potentials with large mass terms and are thus of interest for inflationary model building within string theory. We…
By using the formulation of the reconstruction, we explicitly construct models of $k$-essence, which unify the inflation in the early universe and the late accelerating expansion of the present universe by a single scalar field. Due to the…
We review the recent studies of tachyon condensation in string field theory. After introducing the open string field theory both for bosonic string and for superstring, we use them to examine the conjecture that the unstable configurations…
In bosonic closed string field theory the "tachyon potential" is a potential for the tachyon, the dilaton, and an infinite set of massive fields. Earlier computations of the potential did not include the dilaton and the critical point…
We consider inflation driven near a saddle point in a higher dimensional field space, which is the most likely type of slow roll inflation on the string theoretical landscape; anthropic arguments need to be invoked in order to find a…
We investigate the spacetime-dependent condensation of the tachyon in effective field theories. Previous work identified singularities in the field which appear in finite time: infinite gradients at the kinks, and (in the eikonal…
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…
We consider the linear perturbations for the single scalar field inflation model interacting with an additional triad of scalar fields. The background solutions of the three additional scalar fields depend on spatial coordinates with a…
Cosmological inflation gives a natural answer for a variety of cosmological questions, including the horizon problem, the flatness problem, and others. However, inflation yields new questions relating to the flatness of the inflaton…
These lectures provide an updated pedagogical treatment of the theoretical structure and phenomenology of some basic mechanisms for inflation, along with an overview of the structure of cosmological uplifts of holographic duality. A full…