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We go a step further in the search for a consistent and realistic supergravity model of large-field inflation by building a class of models with the following features: during slow-roll, all the scalar fields other than the inflaton are…

High Energy Physics - Theory · Physics 2015-06-23 Gianguido Dall'Agata , Fabio Zwirner

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field and to perform a general analysis of the associated non-Gaussianities. We investigate the amplitudes and shapes of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Nicola Bartolo , Matteo Fasiello , Sabino Matarrese , Antonio Riotto

We propose a new mechanism to generate density perturbations in inflationary models. Spatial fluctuations in the decay rate of the inflaton field to ordinary matter lead to fluctuations in the reheating temperature. We argue that in most…

Astrophysics · Physics 2009-11-07 Gia Dvali , Andrei Gruzinov , Matias Zaldarriaga

We study stochastic inflation in the presence of a dynamical gravitational constant. We describe the Arnowitt--Deser--Misner formalism for Jordan--Brans--Dicke theory of gravity with an inflaton field. The inflaton and dilaton scalar fields…

Astrophysics · Physics 2009-10-22 Juan Garcia-Bellido

We investigate multi-field signatures of the nonminimally coupled supersymmetric Higgs inflation-type cosmological scenario, focusing on the two-field Higgs-lepton inflation model as a concrete example. This type of inflationary model is…

High Energy Physics - Phenomenology · Physics 2015-12-21 Shinsuke Kawai , Jinsu Kim

We study the slow-roll inflation models, where the inflaton slow-rolls along a trajectory whose orthogonal directions are lifted by potentials with masses of order the Hubble parameter. In these models large non-Gaussianities can be…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Xingang Chen , Yi Wang

We provide a model in which both the inflaton and the curvaton are obtained from within the minimal supersymmetric Standard Model, with known gauge and Yukawa interactions. Since now both the inflaton and curvaton fields are successfully…

High Energy Physics - Phenomenology · Physics 2012-03-14 Anupam Mazumdar , Seshadri Nadathur

A class of non-canonical inflationary models is identified, where the leading-order contribution to the non-Gaussianity of the curvature perturbation is determined by the sound speed of the fluctuations in the inflaton field. Included in…

High Energy Physics - Theory · Physics 2008-11-26 Ian Huston , James E. Lidsey , Steven Thomas , John Ward

We investigate inflationary dynamics in the framework of the Einstein-Gauss-Bonnet gravity. In the model under consideration, the inflaton field is non-minimally coupled to the Gauss-Bonnet curvature invariant, so that the latter appears to…

General Relativity and Quantum Cosmology · Physics 2020-09-02 Ekaterina O. Pozdeeva , Mayukh Raj Gangopadhyay , Mohammad Sami , Alexey V. Toporensky , Sergey Yu. Vernov

We study the scalar-tensor-tensor non-Gaussian signal in an inflationary model comprising also an axion coupled with SU(2) gauge fields. In this set-up, metric fluctuations are sourced by the gauge fields already at the linear level…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-28 Emanuela Dimastrogiovanni , Matteo Fasiello , Robert J. Hardwick , Hooshyar Assadullahi , Kazuya Koyama , David Wands

This paper presents and investigates non-Gaussian perturbations for the warm k-inflation model that is driven by pure kinetic energy. The two complementary components of the overall non-Gaussianity are the three-point and four-point…

General Relativity and Quantum Cosmology · Physics 2023-06-28 Chao-Qun Shen , Xiao-Min Zhang , Zhi-Peng Peng , He Liu , Xi-Bin Li , Peng-Cheng Chu

We describe a two-field model that generalizes Natural Inflation, in which the inflaton is the pseudo-Goldstone boson of an approximate symmetry that is spontaneously broken, and the radial mode is dynamical. We analyze how the dynamics…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-11 Simon Riquelme

Recently multi-field inflation models that can produce large scalar fluctuations on small scales have drawn a lot of attention, primarily because they could lead to primordial black hole production and generation of large second-order…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-21 Laura Iacconi , David J. Mulryne

Tensor non-Gaussianity represents an important future probe of the physics of inflation. Inspired by recent works, we elaborate further on the possibility of significant primordial tensor non-Gaussianities sourced by extra fields during…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-20 Emanuela Dimastrogiovanni , Matteo Fasiello , Gianmassimo Tasinato , David Wands

Any one-field inflation is actually realized in a multifield configuration because the inflaton must have couplings with other fields to reheat the universe and is coupled to all other fields at least gravitationally. In all single inflaton…

High Energy Physics - Phenomenology · Physics 2009-11-11 Masahide Yamaguchi , Jun'ichi Yokoyama

We review the theory of inflation with single and multiple fields paying particular attention to the dynamics of adiabatic and entropy/isocurvature perturbations which provide the primary means of testing inflationary models. We review the…

Astrophysics · Physics 2008-11-26 Bruce A. Bassett , Shinji Tsujikawa , David Wands

We study the effective field theory of inflation, i.e. the most general theory describing the fluctuations around a quasi de Sitter background, in the case of single field models. The scalar mode can be eaten by the metric by going to…

High Energy Physics - Theory · Physics 2009-06-11 Clifford Cheung , Paolo Creminelli , A. Liam Fitzpatrick , Jared Kaplan , Leonardo Senatore

We show that the quantum dynamics of a real scalar field for a large class of potentials in the symmetric Gaussian state, where the nonperturbative quantum contributions are taken into account, can be described equivalently by a…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Dongsu Bak , Sang Pyo Kim , Sung Ku Kim , Kwang-Sup Soh , Jae Hyung Yee

After simplifying and improving the non-Gaussian formalism we developed in previous work, we derive a quantitative expression for the three-point correlator (bispectrum) of the curvature perturbation in general multiple-field inflation…

Astrophysics · Physics 2008-11-26 G. I. Rigopoulos , E. P. S. Shellard , B. J. W. van Tent

Most, if not all, scalar-tensor theories are equivalent to General Relativity with a disformally coupled matter sector. In extra-dimensional theories such a coupling can be understood as a result of induction of the metric on a brane that…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-22 Carsten van de Bruck , Tomi Koivisto , Chris Longden