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We compute the power spectrum of curvature perturbations in stochastic inflation. This combines the distribution of first crossing times through the end-of-inflation surface, which has been previously studied, with the distribution of the…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-27 Kenta Ando , Vincent Vennin

We estimate large-scale curvature perturbations from isocurvature fluctuations in the waterfall field during hybrid inflation, in addition to the usual inflaton field perturbations. The tachyonic instability at the end of inflation leads to…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 José Fonseca , Misao Sasaki , David Wands

Motivated by the prospect of testing inflation from precision cosmic microwave background observations, we present analytic results for scalar and tensor perturbations in single-field inflation models based on the application of uniform…

Astrophysics · Physics 2009-11-07 Salman Habib , Katrin Heitmann , Gerard Jungman , Carmen Molina-Paris

We calculate the quadra-spectrum and quint-spectrum, corresponding to five and six point correlation functions of the curvature perturbation. For single field inflation with standard kinetic term, the quadra-spectrum and quint-spectrum are…

Cosmology and Nongalactic Astrophysics · Physics 2010-08-16 Chunshan Lin , Yi Wang

The inflationary and pre-inflationary evolution of scalar modes of cosmological perturbations in a closed universe is analyzed for a loop quantum cosmology model with an inflationary regime consistent with the constraints on inflation…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Lucas M. V. Montese , Nelson Yokomizo

We study adiabatic and isocurvature perturbations produced during a period of cosmological inflation. We compute the power spectra and cross spectra of the curvature and isocurvature modes, as well as the tensor perturbation spectrum in…

Astrophysics · Physics 2009-11-06 N. Bartolo , S. Matarrese , A. Riotto

We study the amplitude and spectral tilt of density perturbations in the simplest hybrid inflation models. We give an exact expression for the amplitude of quantum fluctuations on all scales in the limit where we can neglect the…

Astrophysics · Physics 2009-06-19 Juan Garcia-Bellido , David Wands

We investigate the effects of couplings between curvature and isocurvature perturbations before and around horizon-crossings during cosmological inflation. We consider a generalized two-field inflation model, in which the non-canonical…

High Energy Physics - Theory · Physics 2010-02-18 Xian Gao

We calculate the three-point correlation function of the comoving curvature perturbation generated during an inflationary epoch driven by false vacuum energy. We get a novel false vacuum shape bispectrum, which peaks in the equilateral…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Jinn-Ouk Gong , Chunshan Lin , Yi Wang

We set up a formalism that can be used to calculate the power spectrum of the curvature perturbations produced during inflation up to arbitrary order in the slow-roll expansion, and explicitly calculate the power spectrum and spectral index…

Astrophysics · Physics 2009-11-06 Ewan D. Stewart , Jin-Ook Gong

We present a mechanism for the origin of the large-scale curvature perturbation in our Universe by the late decay of a massive scalar field, the curvaton. The curvaton is light during a period of cosmological inflation, when it acquires a…

High Energy Physics - Phenomenology · Physics 2010-02-18 David H. Lyth , David Wands

The curvaton scenario predicts an almost scale-invariant spectrum of perturbations in most inflation models. We consider the possibility that renormalisable phi^4 or Planck scale-suppressed non-renormalisable curvaton potential terms may…

High Energy Physics - Phenomenology · Physics 2009-11-10 John McDonald

Curvature perturbations generated after the end of inflation are estimated for a generic multi-field inflationary potential. The curvature perturbations are generated by conversion of inflationary isocurvature perturbations, similar to…

Astrophysics · Physics 2007-05-23 Andrei Gruzinov

Cosmological perturbations, originating in the quantum fluctuations of the fields that drive inflation, are observed to be nearly scale invariant at the largest scales. At smaller scales, however, perturbations are not severely constrained…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-09 Ioannis Dalianis

During inflationary preheating, the energy stored in the inflaton field is rapidly converted into excitations of other entropy fields. This stage is characterized by exponential particle production due to parametric resonance and is…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-15 Jie Jiang , Qiuyue Liang , Yi-Fu Cai , Damien A. Easson , Yang Zhang

In this paper, we have studied the spectrum of curvature perturbation of multi-field inflation with general small-field potential. We assume that the isocurvature perturbation may be neglected, and by using the Sasaki-Stewart formalism, we…

Astrophysics · Physics 2009-06-23 Iftikhar Ahmad , Yun-Song Piao , Cong-Feng Qiao

We compute the power spectrum of super-horizon curvature perturbations generated during a late period of thermal inflation, taking into account fluctuation-dissipation effects resulting from the scalar flaton field's interactions with the…

High Energy Physics - Phenomenology · Physics 2024-07-22 Mar Bastero-Gil , Joaquim M. Gomes , João G. Rosa

The spectral index is studied at the point where scalar fields deviate from slow-roll during inflation. Considering the deviation that may cause a significant difference to the time derivative of the Hubble parameter and also to the terms…

High Energy Physics - Phenomenology · Physics 2010-04-21 Tomohiro Matsuda

We study the generation of the primordial curvature perturbation in multi-field inflation. Considering both the evolution of the perturbation during inflation and the effects generated at the end of inflation, we present a general formula…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Ki-Young Choi , Soo A Kim , Bumseok Kyae

Trapped inflation is a mechanism in which particle production from the moving inflaton is the main source of friction in the inflaton equation of motion. The produced fields source inflaton perturbations, which dominate over the vacuum…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-09 Lauren Pearce , Marco Peloso , Lorenzo Sorbo