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The scalar mode density perturbations in a the warm inflationary scenario are analysed with a view to predicting the amount of non-gaussianity produced by this scenario. The analysis assumes that the inflaton evolution is strongly damped by…

Astrophysics · Physics 2010-10-27 Ian G Moss , Chun Xiong

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

Using the techniques of out-of-equilibrium field theory, we study the influence on the properties of cosmological perturbations generated during inflation on observable scales coming from fluctuations corresponding today to scales much…

High Energy Physics - Theory · Physics 2009-11-10 Sabino Matarrese , Marcello A. Musso , Antonio Riotto

We identify a new inflationary regime for which more than 60 e-folds are generated classically during the waterfall phase occuring after the usual hybrid inflation. By performing a bayesian Monte-Carlo-Markov-Chain analysis, this scenario…

General Relativity and Quantum Cosmology · Physics 2011-03-22 Sebastien Clesse

We study multi-field DBI inflation models with a waterfall phase transition. This transition happens for a D3 brane moving in the warped conifold if there is an instability along angular directions. The transition converts the angular…

Cosmology and Nongalactic Astrophysics · Physics 2012-11-29 Taichi Kidani , Kazuya Koyama , Shuntaro Mizuno

We consider the expected level of primordial non-Gaussianities in models in which density perturbations are produced by spatial fluctuations in the decay rate of the inflaton. We consider both the non-Gaussianities resulting from the…

Astrophysics · Physics 2008-11-26 Matias Zaldarriaga

Long-short mode coupling during inflation, encoded in the squeezed bispectrum of curvature perturbations, induces a dependence of the local, small-scale power spectrum on long-wavelength perturbations, leading to a scale-dependent halo…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Giovanni Cabass , Enrico Pajer , Fabian Schmidt

In this study, we explore the back reaction of phase transitions in the spectator sector on the inflaton field during slow-roll inflation. Due to the significant excursion of the inflaton field, these phase transitions are likely to occur…

High Energy Physics - Phenomenology · Physics 2024-11-20 Haipeng An , Qi Chen , Yuhang Li , Yuan Yin

We compute the probability density distribution of maxima for a scalar random field in the presence of local non-gaussianities. The physics outcome of this analysis is the following. If we focus on maxima whose curvature is larger than a…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-08 Flavio Riccardi , Marco Taoso , Alfredo Urbano

We study the effect of non-trivial sound speeds on local-type non-Gaussianity during multiple-field inflation. To this end, we consider a model of multiple-field DBI and use the deltaN formalism to track the super-horizon evolution of…

High Energy Physics - Theory · Physics 2012-08-07 Jon Emery , Gianmassimo Tasinato , David Wands

Noncommutative geometry can provide effective description of physics at very short distances taking into account generic effects of quantum gravity. Inflation amplifies tiny quantum fluctuations in the early universe to macroscopic scales…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-18 Tomi S. Koivisto , David F. Mota

This talk briefly explains how the breaking of a Lorentz-invariant description of nature at tiny space-time intervals might affect the non-Gaussian character of the primordial fluctuations left by inflation. For example, a model that…

High Energy Physics - Theory · Physics 2014-11-20 Hael Collins

I summarize recent work on (1) constraining spike-like features in the cosmic microwave background and large scale structure; (2) nonstandard Friedmann equation in stabilized warped 6D brane cosmology, with applications to inflation; and…

Astrophysics · Physics 2008-05-15 James M. Cline

We present a gauge-invariant formalism to study the evolution of the curvature and entropy perturbations in the case in which spatial and time variations of the inflaton decay rate into ordinary matter are present. During the reheating…

Astrophysics · Physics 2009-11-10 Sabino Matarrese , Antonio Riotto

Multi-natural inflation is studied in the context of warm inflation. We study the warm multi-natural inflation scenario with both linear and cubic temperature-dependent dissipation coefficients. The model is motivated by axion-like…

High Energy Physics - Phenomenology · Physics 2025-09-01 Asuka Ito , Rudnei O. Ramos

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

Typically cold inflation with positive vacuum energy density dilutes all matter except the quan- tum fluctuations which are stretched outside the Hubble patch during inflation. However the cyclic- inflation scenario, where the universe…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Tirthabir Biswas , Tomi Koivisto , Anupam Mazumdar

While moving down the potential on its classical slow roll trajectory, the inflaton field is subject to quantum jumps, which take it up or down the potential at random. In "stochastic inflation", the impact of these quantum jumps is modeled…

High Energy Physics - Theory · Physics 2015-05-20 Larissa Lorenz

In this letter we study adiabatic and isocurvature perturbations in the frame of inflation with multiple sound speeds involved. We suggest this scenario can be realized by a number of generalized scalar fields with arbitrary kinetic forms.…

High Energy Physics - Theory · Physics 2010-12-17 Yi-Fu Cai , Hai-Ying Xia

Inflating curvaton can create curvature perturbation when the curvaton density is slowly varying. Using the delta-N formalism, we discuss the evolution of the curvature perturbation during curvaton inflation and find analytic formulation of…

High Energy Physics - Phenomenology · Physics 2013-06-26 Seishi Enomoto , Kazunori Kohri , Tomohiro Matsuda