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Related papers: Non-Gaussianity in KKLMMT model

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The presence of multiple fields during inflation might seed a detectable amount of non-Gaussianity in the curvature perturbations, which in turn becomes observable in present data sets like the cosmic microwave background (CMB) or the large…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-27 Sebastian Dorn , Erandy Ramirez , Kerstin E. Kunze , Stefan Hofmann , Torsten A. Enßlin

We discuss various realizations of the four dimensional braneworld inflation in warped geometries of string theory. In all models the inflaton field is represented by a Dp probe brane scalar specifying its position in the warped throat of…

High Energy Physics - Theory · Physics 2009-11-10 Alex Buchel , Ahmad Ghodsi

We investigate non-Gaussianity in general single field models without assuming slow-roll conditions or the exact scale-invariance of the scalar power spectrum. The models considered include general single field inflation (e.g. DBI and…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-13 Johannes Noller , Joao Magueijo

We discuss how primordial non-Gaussianity of the curvature perturbation helps to constrain models of the early universe. Observations are consistent with Gaussian initial conditions, compatible with the predictions of the simplest models of…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-26 Christian T. Byrnes

Many existing models of brane inflation suffer from a steep irreducible gravitational potential between the branes that causes inflation to end too early. Inspired by the fact that point masses in 2+1 D exert no gravitational force, we…

High Energy Physics - Theory · Physics 2010-05-12 Jason Gallicchio , Rakhi Mahbubani

We investigate the embedding of brane anti-brane inflation into a concrete type IIB string theory compactification with all moduli fixed. Specifically, we are considering a D3-brane, whose position represents the inflaton $\phi$, in a…

High Energy Physics - Theory · Physics 2009-04-17 Axel Krause , Enrico Pajer

We study multifield aspects of Dirac-Born-Infeld (DBI) inflation. More specifically, we consider an inflationary phase driven by the radial motion of a D-brane in a conical throat and determine how the D-brane fluctuations in the angular…

High Energy Physics - Theory · Physics 2014-11-20 Sébastien Renaux-Petel

We discuss phenomenological aspects of no-scale supergravity inflationary models motivated by compactified string models, in which the inflaton may be identified either as a K\"ahler modulus or an untwisted matter field, focusing on models…

High Energy Physics - Phenomenology · Physics 2015-10-07 John Ellis , Marcos A. G. Garcia , Dimitri V. Nanopoulos , Keith A. Olive

We study the non-gaussianity from the bispectrum in multi-field inflation models with a general kinetic term. The models include the multi-field K-inflation and the multi-field Dirac-Born-Infeld (DBI) inflation as special cases. We find…

High Energy Physics - Theory · Physics 2011-02-07 Frederico Arroja , Shuntaro Mizuno , Kazuya Koyama

We consider a generalization of the Randall-Sundrum single brane-world scenario (RS2). More precisely, the generalization is described through curvature corrections, corresponding to a Gauss-Bonnet term in the bulk and a Hilbert-Einstein…

General Relativity and Quantum Cosmology · Physics 2013-05-30 Mariam Bouhmadi-Lopez , Pisin Chen , Yen-Wei Liu

An inflationary brane model driven by a bulk inflaton with exponential potential is proposed. We find a family of exact solutions that describe power-law inflation on the brane. These solutions enable us to derive exact solutions for metric…

High Energy Physics - Theory · Physics 2009-11-10 Kazuya Koyama , Keitaro Takahashi

We investigate a new way of realizing a period of cosmological inflation in the context of brane gas cosmology. It is argued that a gas of co-dimension one branes, out of thermal equilibrium with the rest of the matter, has an equation of…

High Energy Physics - Theory · Physics 2007-05-23 Robert Brandenberger , Damien A. Easson , Anupam Mazumdar

The distance between BPS branes in string theory corresponds to a flat direction in the effective potential. Small deviations from supersymmetry may lead to a small uplifting of this flat direction and to brane inflation. However, this…

High Energy Physics - Theory · Physics 2008-11-26 Jonathan P. Hsu , Renata Kallosh , Sergey Prokushkin

Using the "$\delta N$-formalism", We obtain the expression of the non-Gaussianity of multiple-field inflationary models with the nontrivial field-space metric. Further, we rewritten the result by using the slow-rolling approximation.

Astrophysics · Physics 2009-11-11 C. Y. Sun , D. H. Zhang

A quantum-mechanical technique is used within the framework of U(2) super-Yang-Mills theory to investigate processes after recombination of two D-p-branes at one angle. Two types of initial conditions are considered, one of which with $p=4$…

High Energy Physics - Theory · Physics 2007-05-23 Takeshi Sato

The bispectrum of scalar mode density perturbations is analysed for the strong regime of warm inflationary models. This analysis generalises previous results by allowing damping terms in the inflaton equation of motion that are dependent on…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Ian G Moss , Timothy Yeomans

The scenario of brane inflation without using the conventional slow-roll approximations has been investigated. Based on the mechanism of generating the curvature perturbations at the end of inflation, a new brane inflation paradigm was…

Astrophysics · Physics 2010-10-27 Tomohiro Matsuda

We examine the effective theory of single-field inflation in the limit where the scalar perturbations propagate with a small speed of sound. In this case the non-linearly realized time-translation symmetry of the Lagrangian implies large…

High Energy Physics - Theory · Physics 2015-05-27 Daniel Baumann , Daniel Green

We propose a new model of slow-roll inflation in string cosmology, based on warped throat supergravity solutions displaying `walking' dynamics, i.e. the coupling constant of the dual gauge theory slowly varies over a range of energy scales.…

High Energy Physics - Theory · Physics 2015-06-11 Johanna Erdmenger , Sebastian Halter , Carlos Nunez , Gianmassimo Tasinato

We describe a model of P-term inflation on D5 branes wrapped on resolved and deformed $A_n$ type singularities. On the brane world--volume the resolution and deformation of the singularity correspond to an anomalous D-term and a linear term…

High Energy Physics - Theory · Physics 2007-05-23 Edi Halyo