English
Related papers

Related papers: A Fast and Accurate Algorithm for Computing Tensor…

200 papers

It is plausible that the scalar density perturbations are created by a relatively low scale model of inflation which predicts the CMB anisotropy and excites Standard Model baryon and cold dark matter, but negligible gravity waves.…

Astrophysics · Physics 2008-04-03 Rouzbeh Allahverdi , Anupam Mazumdar , Tuomas Multamaki

We investigate the possibility that the amplitude of scalar density perturbations may be damped after inflation. This would imply that CMB anisotropies do not uniquely fix the amplitude of the perturbations generated during inflation and…

Astrophysics · Physics 2009-11-11 N. Bartolo , Edward W. Kolb , A. Riotto

The presence of a light vector field coupled to a scalar field during inflation makes a distinct prediction: the observed correlation functions of the cosmic microwave background (CMB) become statistically anisotropic. We study the…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-24 Atsushi Naruko , Eiichiro Komatsu , Masahide Yamaguchi

We examine stochastic temperature fluctuations of the cosmic background radiation (CBR) arising via the Sachs-Wolfe effect from gravitational wave perturbations produced in the early universe. We consider spatially flat, perturbed FRW…

Astrophysics · Physics 2009-10-22 Scott Koranda , Bruce Allen

The cosmic microwave background (CMB) carries information from the last scattering surface that puts constraints on the multitude of proposed cosmological models and the gravitation theories they are based on. One class of such theories is…

General Relativity and Quantum Cosmology · Physics 2013-02-11 Hassan Bourhrous

The increasing precision of cosmological datasets is opening up new opportunities to test predictions from cosmic inflation. Here we study the impact of high precision constraints on the primordial power spectrum and show how a new…

Astrophysics · Physics 2010-04-08 Benjamin Gold , Andreas Albrecht

Effect of non-canonical scalar fields on the CMB imprints of the anisotropic inflation will be discussed in details in this paper. In particular, we are able to obtain the general formalism of the angular power spectra in the scalar…

General Relativity and Quantum Cosmology · Physics 2021-05-07 Tuan Q. Do , W. F. Kao , Ing-Chen Lin

Inflation in a five-dimensional brane world model with two boundary branes is studied. We make use of the moduli space approximation whereby the low energy theory reduces to a four-dimensional biscalar-tensor gravity plus a minimally…

We investigate a possibility of constraining statistical anisotropies of the primordial tensor perturbations by using future observations for the Cosmic Microwave Background (CMB) B-mode polarization. By parameterizing a…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-24 Takashi Hiramatsu , Shuichiro Yokoyama , Tomohiro Fujita , Ippei Obata

In this paper, inflationary cosmology is reviewed, paying particular attention to its observational signatures associated with large-scale density perturbations generated from quantum fluctuations. In the most general scalar-tensor theories…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-13 Shinji Tsujikawa

We present the status of our study into the feasibility of estimating the parameters of inflation from planned satellite observations of the anisotropy of the cosmic microwave background (CMB).We describe a perturbative procedure for…

We investigate the hemispherical power asymmetry observed in the CMBR by attributing it to an early inhomogeneous phase of cosmic expansion. Unlike the conventional assumption of a perfectly isotropic and homogeneous pre-inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-30 Akash Gandhi , Mohit Panwar , Pankaj Jain

It is commonly assumed that the stochastic background of gravitational waves on cosmological scales follows an almost scale-independent power spectrum, as generically predicted by the inflationary paradigm. However, it is not inconceivable…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-14 Jan Hamann , Ameek Malhotra

In the near future, observations of the cosmic microwave background (CMB) anisotropies will provide accurate determinations of many fundamental cosmological parameters. In this paper, we analyse degeneracies among cosmological parameters to…

Astrophysics · Physics 2009-10-30 G. Efstathiou , J. R. Bond

We generalize the treatment of inflationary perturbations to deal with the non-Markovian colored noise emerging from any realistic approach to stochastic inflation. We provide a calculation of the power-spectrum of the gauge-invariant…

Astrophysics · Physics 2009-11-10 M. Liguori , S. Matarrese , M. Musso , A. Riotto

The Cosmic Microwave Background (CMB) anisotropy power on the largest angular scales observed both by WMAP and COBE DMR appears to be lower than the one predicted by the standard model of cosmology with almost scale free primordial…

Astrophysics · Physics 2009-09-29 Carlo R. Contaldi , Marco Peloso , Lev Kofman , Andrei Linde

Recent cosmic microwave background (CMB) observations put strong constraints on the spatial curvature via estimation of the parameter $\Omega_k$ assuming an almost scale invariant primordial power spectrum. We study the evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-31 Béatrice Bonga , Brajesh Gupt , Nelson Yokomizo

Forthcoming cosmic microwave background experiments (CMB) will provide precise new tests of structure-formation theories. The geometry of the Universe may be determined robustly, and the classical cosmological parameters, such as the…

Astrophysics · Physics 2007-05-23 Marc Kamionkowski

This article provides an introductory review of inflation and cosmological perturbation theory. I begin by motivating the need for an epoch of inflation during the early stages of the radiation dominated era, and describe how inflation is…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-08 L. Sriramkumar

Inflationary cosmology has proved to be the most successful at predicting the properties of the anisotropies observed in the cosmic microwave background (CMB). In this essay we show that quantum field renormalization significantly…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Ivan Agullo , Jose Navarro-Salas , Gonzalo J. Olmo , Leonard Parker