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We derive analytic bounds on the shape of the primordial power spectrum in the context of single-field inflation. In particular, the steepest possible growth has a spectral index of $n_s - 1 = 4$ once transients have died down. Its primary…

宇宙学与河外天体物理 · 物理学 2019-06-24 Christian T. Byrnes , Philippa S. Cole , Subodh P. Patil

We propose a general inverse formula for extracting inflationary parameters from the observed power spectrum of cosmological perturbations. Under the general slow-roll scheme, which helps to probe the properties of inflation in a model…

天体物理学 · 物理学 2009-11-10 Minu Joy , Ewan D. Stewart , Jinn-Ouk Gong , Hyun-Chul Lee

The stochastic gravitational wave background (SGWB) detected recently by the pulsar timing arrays (PTAs) observations may have cosmological origins. In this work we consider a model of single field inflation containing an intermediate phase…

广义相对论与量子宇宙学 · 物理学 2023-10-10 Hassan Firouzjahi , Alireza Talebian

We study the production of scalar-induced gravitational waves and primordial black holes in a single-field inflation model with a localized bump or dip feature in the potential. Introducing such a localized feature temporarily decelerates…

宇宙学与河外天体物理 · 物理学 2026-03-13 Xiang Zhang , Zhao-Huan Yu

We develop a fast technique based on the generalized slow roll (GSR) approach for computing the curvature bispectrum of inflationary models with features. We show that all triangle configurations can be expressed in terms of three simple…

宇宙学与河外天体物理 · 物理学 2012-03-02 Peter Adshead , Wayne Hu , Cora Dvorkin , Hiranya V. Peiris

We present a complete numerical treatment of inflationary dynamics under the influence of stochastic corrections from sub-Hubble modes. We discuss how to exactly model the stochastic noise terms arising from the sub-Hubble quantum modes…

宇宙学与河外天体物理 · 物理学 2020-12-02 Aritra De , Rafid Mahbub

Numerical simulations of the inflationary dynamics are presented here for a single canonical scalar field minimally coupled to gravity. We spell out the basic equations governing the inflationary dynamics in terms of cosmic time $t$ and…

广义相对论与量子宇宙学 · 物理学 2024-08-29 Siddharth S. Bhatt , Swagat S. Mishra , Soumen Basak , Surya N. Sahoo

During the inflationary epoch,geometry of the universe may be described by quasi-de Sitter space. On the other hand,maximally extended de Sitter metric in the comoving coordinates accords with a special FLRW model with positive spatial…

广义相对论与量子宇宙学 · 物理学 2016-01-20 A. A. Asgari , A. H. Abbassi

We revisit the one-loop correction in curvature perturbation power spectrum in models of single field inflation which undergo a phase of ultra slow-roll (USR) inflation. We include the contributions from both the cubic and quartic…

宇宙学与河外天体物理 · 物理学 2023-10-06 Hassan Firouzjahi

We investigate the cosmic inflation within a class of the scalar-tensor model with the scalar-dependent non-minimal kinetic couplings. The inflationary dynamical potential will be applied. Using the slow-roll approximation, we compute…

广义相对论与量子宇宙学 · 物理学 2025-12-01 Feyzollah Younesizadeh , Davoud Kamani

We consider a cosmological inflation scenario based on a no-scale supergravity sector with $U(1)_R$ symmetry. It is shown that a tree level $U(1)_R$ symmetric superpotential alone does not lead to a slowly rolling scalar potential. A…

高能物理 - 唯象学 · 物理学 2019-05-29 Shaaban Khalil , Ahmad Moursy , Abhijit Kumar Saha , Arunansu Sil

We propose new versions of the slow-roll approximation for inflationary models with nonminimally coupled scalar fields. We derive more precise expressions for the standard slow-roll parameters as functions of the scalar field. To verify the…

广义相对论与量子宇宙学 · 物理学 2025-05-30 Ekaterina O. Pozdeeva , Maria A. Skugoreva , Alexey V. Toporensky , Sergey Yu. Vernov

We derive the power spectrum P_\psi(k) of the gravitational waves produced during general classes of inflation with second order corrections. Using this result, we also derive the spectrum and the spectral index in the standard slow-roll…

广义相对论与量子宇宙学 · 物理学 2009-11-10 Jinn-Ouk Gong

Measuring the primordial power spectrum on small scales is a powerful tool in inflation model building, yet constraints from Cosmic Microwave Background measurements alone are insufficient to place bounds stringent enough to be appreciably…

宇宙学与河外天体物理 · 物理学 2012-09-27 Laila Alabidi , Kazunori Kohri , Misao Sasaki , Yuuiti Sendouda

An inflationary scenario driven by a slow rolling homogeneous scalar field whose potential $V(\Phi)$ is given by a generalized exponential function is discussed. Within the {\sl slow-roll} approximation we investigate some of the main…

天体物理学 · 物理学 2008-11-26 J. S. Alcaniz , F. C. Carvalho

In the standard inflationary paradigm, cosmological density perturbations are generated as quantum fluctuations in the early Universe, but then undergo a quantum-to-classical transition. A key role in this transition is played by squeezing…

广义相对论与量子宇宙学 · 物理学 2020-02-19 Roland de Putter , Olivier Doré

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…

广义相对论与量子宇宙学 · 物理学 2024-11-26 Lucas M. V. Montese , Nelson Yokomizo

We study an inflationary scenario where thermal inflation is followed by fast-roll inflation. This is a rather generic possibility based on the effective potentials of spontaneous symmetry breaking in the context of particle physics models.…

高能物理 - 唯象学 · 物理学 2008-11-26 Jinn-Ouk Gong

The decrease of both the rolling speed of the inflaton and the sound speed of the curvature perturbations can amplify the curvature perturbations during inflation so as to generate a sizable amount of primordial black holes. In the…

广义相对论与量子宇宙学 · 物理学 2024-01-17 Rongrong Zhai , Hongwei Yu , Puxun Wu

We study higher curvature corrections to the scalar spectral index, the tensor spectral index, the tensor-to-scalar ratio, and the polarization of gravitational waves. We find that the higher curvature corrections can not be negligible in…

天体物理学 · 物理学 2011-07-13 Masaki Satoh , Jiro Soda