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Provided the quantum fluctuations are amplified in the presence of a classical gauge field configuration the resulting curvature perturbations exhibit a mild statistical anisotropy which should be sufficiently weak not to conflict with…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-09 Massimo Giovannini

We investigate the spatial profile of the curvature perturbation generated in multi-waterfall hybrid inflation models, which are known to produce various topological defects. Using the lattice simulation code \acl{STOLAS}, based on the…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-06 Tomoaki Murata , Yuichiro Tada

We introduce a new method for calculating density perturbations in hybrid inflation which avoids treating the fluctuations of the "waterfall" field as if they were small perturbations about a classical trajectory. We quantize only the…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-01 Alan H. Guth , Evangelos I. Sfakianakis

Solid inflation can support a long period of anisotropic inflation. We calculate the statistical anisotropies in the scalar and tensor power spectra and their cross-correlation in anisotropic solid inflation. The tensor-scalar…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Mohammad Akhshik , Razieh Emami , Hassan Firouzjahi , Yi Wang

We revisit the dynamics of the axial coupling between many N-flatons and an Abelian gauge field, with special attention to its statistically anisotropic signal. The anisotropic power spectrum of curvature perturbations associated to the…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-02 Federico R. Urban

The decay of massive particles during inflation generates characteristic signals in the squeezed limit of the primordial bispectrum. These signals are in particular distinctive in the regime of the quasi-single field inflation, where…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-08 Yi Wang , Yi-Peng Wu , Jun'ichi Yokoyama , Siyi Zhou

Global topological defects may account for the large cold spot observed in the Cosmic Microwave Background. We explore possibilities of constructing models of supersymmetric F-term hybrid inflation, where the waterfall fields are globally…

High Energy Physics - Phenomenology · Physics 2008-11-26 Richard A. Battye , Bjorn Garbrecht , Apostolos Pilaftsis

A suitable coupling of the inflaton phi to a vector kinetic term F^2 gives frozen and scale invariant vector perturbations. We compute the cosmological perturbations zeta that result from such coupling by taking into account the classical…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Nicola Bartolo , Sabino Matarrese , Marco Peloso , Angelo Ricciardone

In this paper the possibility of generating large scale curvature perturbations induced from the entropic perturbations during the waterfall phase transition of standard hybrid inflation model is studied. We show that whether or not…

High Energy Physics - Theory · Physics 2011-03-22 Ali Akbar Abolhasani , Hassan Firouzjahi

Motivated by the interest in models of the early universe where statistical isotropy is broken and can be revealed in cosmological observations, we consider an SU(2) theory of gauge interactions in a single scalar field inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Nicola Bartolo , Emanuela Dimastrogiovanni , Sabino Matarrese , Antonio Riotto

We study single field inflation in noncommutative spacetime and compute two-point and three-point correlation functions for the curvature perturbation. We find that both power spectrum and bispectrum for comoving curvature perturbation are…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-20 Akhilesh Nautiyal

We revisit the idea of generating primordial anisotropies at the end of inflation in models of inflation with gauge fields. To be specific we consider the charged hybrid inflation model where the waterfall field is charged under a U(1)…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Razieh Emami , Hassan Firouzjahi

The \delta N formula for the primordial curvature perturbation \zeta is extended to include vector as well as scalar fields. Formulas for the tree-level contributions to the spectrum and bispectrum of \zeta are given, exhibiting statistical…

We consider a primordial SU(2) vector multiplet during inflation in models where quantum fluctuations of vector fields are involved in producing the curvature perturbation. Recently, a lot of attention has been paid to models populated by…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-13 Nicola Bartolo , Emanuela Dimastrogiovanni , Sabino Matarrese , Antonio Riotto

Cosmological inflation remains to be a unique mechanism of generation of plausible initial conditions in the early universe. In particular, it generates the primordial quasiclassical perturbations with power spectrum determined by the…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-23 Yuri Shtanov

We propose a hybrid inflation model with a complex waterfall field which contains an interaction term that breaks the U(1) global symmetry associated to the waterfall field charge. We show that the asymmetric evolution of the real and…

High Energy Physics - Phenomenology · Physics 2008-11-26 David Delepine , Carlos Martinez , L. Arturo Urena-Lopez

We consider a variant of hybrid inflation where the waterfall phase transition happens during inflation. By adjusting the parameters associated with the mass of the waterfall field we arrange that the phase transition is not sharp so…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Ali Akbar Abolhasani , Hassan Firouzjahi , Mohammad Hossein Namjoo

We extend a recently proposed framework, dubbed inflation by supersymmetry breaking, to hybrid inflation by introducing a waterfall field that allows to decouple the supersymmetry breaking scale in the observable sector from the inflation…

High Energy Physics - Theory · Physics 2025-12-16 Yermek Aldabergenov , Ignatios Antoniadis , Auttakit Chatrabhuti , Hiroshi Isono

We study the statistical nature of primordial fluctuations from an anisotropic inflation which is realized by a vector field coupled to an inflaton. We find a suitable gauge, which we call the canonical gauge, for anisotropic inflation by…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-27 Masa-aki Watanabe , Sugumi Kanno , Jiro Soda

We construct a hybrid-inflation model where the inflaton potential is generated radiatively, as gauge symmetries guarantee it to be accidentally flat at tree level. The model can be regarded as a small-field version of Natural Inflation,…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-18 Felix Brümmer , Giacomo Ferrante , Michele Frigerio