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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…

Astrophysics · Physics 2010-12-02 Erandy Ramirez , Tonatiuh Matos

We initially consider two simple situations where inflationary slow roll parameters are large and modes no longer freeze out shortly after exiting the horizon, treating both cases analytically. We then consider applications to transient…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-03 Jessica L. Cook , Lawrence M. Krauss

We present a new class of two-field inflationary attractor models, known as `shift-symmetric orbital inflation', whose behaviour is strongly multi-field but whose predictions are remarkably close to those of single-field inflation. In these…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Ana Achúcarro , Edmund J. Copeland , Oksana Iarygina , Gonzalo A. Palma , Dong-Gang Wang , Yvette Welling

I investigate multi-field inflationary models with fields that decay during inflation, leading to staggered inflation. This feature is natural in many models motivated by string theory, for instance if inflatons are related to interbrane…

Astrophysics · Physics 2010-01-08 Thorsten Battefeld

A systematic analysis of possibilities for realizing single-field F-term axion monodromy inflation via the flux-induced superpotential in type IIB string theory is performed. In this well-defined setting the conditions arising from moduli…

High Energy Physics - Theory · Physics 2015-01-14 Ralph Blumenhagen , Daniela Herschmann , Erik Plauschinn

Inflation is the currently accepted paradigm for the beginnings of the Universe. To explain the observed almost scale invariant spectrum of density perturbations with only a slight spectral tilt, inflation must have been "slow roll", that…

High Energy Physics - Theory · Physics 2021-01-07 Hao Geng

In this paper we investigate the implications of having a varying second slow-roll index on the canonical scalar field inflationary dynamics. We shall be interested in cases that the second slow-roll can take small values and…

General Relativity and Quantum Cosmology · Physics 2017-05-03 S. D. Odintsov , V. K. Oikonomou

We construct a string-inspired nonsingular cosmological scenario in which an inflaton field is driven up the potential before the graceful exit by employing a low-energy string effective action with an orbifold compactification. This sets…

High Energy Physics - Theory · Physics 2015-06-26 Yun-Song Piao , Shinji Tsujikawa , Xinmin Zhang

The slow-roll field equations for the case of non-minimally coupled scalar fields are obtained in two ways: first using the direct generalization of slow-roll conditions in the minimal coupling case to non-minimal one; and, second,…

General Relativity and Quantum Cosmology · Physics 2016-08-08 A. Savas Arapoglu

We investigate slow-roll inflation in a multi-field random Gaussian landscape. The landscape is assumed to be small-field, with a correlation length much smaller than the Planck scale. Inflation then typically occurs in small patches of the…

High Energy Physics - Theory · Physics 2018-02-13 Ali Masoumi , Alexander Vilenkin , Masaki Yamada

In this paper the focus is on inflationary dynamics in the context of Einstein Gauss-Bonnet gravitational theories. We investigate the implications of the slow-roll condition on the slow-roll indices and we investigate how the inflationary…

General Relativity and Quantum Cosmology · Physics 2018-09-26 S. D. Odintsov , V. K. Oikonomou

We study how both the swampland distance conjecture and the Lyth bound affect the parameter space of multi-field models of inflation. A generic feature of multi-field inflation is that the geodesic distance…

High Energy Physics - Theory · Physics 2020-02-12 Rafael Bravo , Gonzalo A. Palma , Simon Riquelme

We generalize the consistency condition for the three-point function in single field inflation to the case of dissipative, multi-field, single-clock models. We use the recently introduced extension of the effective field theory of inflation…

High Energy Physics - Theory · Physics 2015-06-05 Diana Lopez Nacir , Rafael A. Porto , Matias Zaldarriaga

We present a simple effective field theory formulation of a general family of single field flux monodromy models for which strong coupling effects at large field values can flatten the potential and activate operators with higher powers of…

High Energy Physics - Theory · Physics 2018-09-12 Guido D'Amico , Nemanja Kaloper , Albion Lawrence

Non-supersymmetric brane world scenarios in string theory display perturbative instabilities that usually involve run-away potentials for scalar moduli fields. We investigate in the framework of intersecting brane worlds whether the leading…

High Energy Physics - Theory · Physics 2009-10-07 Ralph Blumenhagen , Boris Kors , Dieter Lust , Tassilo Ott

The methods of supergravity allow us to derive a multi-field F-term potential. Using this, we denote a generic and non-positive single-field F-term potential. We insert our theory into the scalar-gravity part of the $SU(2,1|1)$ invariant…

High Energy Physics - Theory · Physics 2021-04-12 Ugur Atli , Omer Guleryuz

Hybrid inflation can be realised in low-energy effective string theory, as described using supergravity. We find that the coupling of moduli to F-term hybrid inflation in supergravity leads to a slope and a curvature for the inflaton…

High Energy Physics - Theory · Physics 2009-11-11 Ph. Brax , C. van de Bruck , A. C. Davis , Stephen C. Davis

We study adiabatic and isocurvature perturbation spectra produced by a period of cosmological inflation driven by two scalar fields. We show that there exists a model-independent consistency condition for all two-field models of slow-roll…

Astrophysics · Physics 2009-11-07 David Wands , Nicola Bartolo , Sabino Matarrese , Antonio Riotto

We study models of inflation with two scalar fields and non-canonical kinetic terms, focusing on the case in which the curvature and isocurvature perturbations are strongly coupled to each other. In the regime where a heavy mode can be…

High Energy Physics - Theory · Physics 2011-03-10 Sera Cremonini , Zygmunt Lalak , Krzysztof Turzynski

An appealing feature of inflationary cosmology is the presence of a phase-space attractor, "slow roll", which washes out the dependence on initial field velocities. We investigate the robustness of this property under backreaction from…

General Relativity and Quantum Cosmology · Physics 2021-04-05 Julien Grain , Vincent Vennin