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The present work begins by examining the early-Universe inflationary epoch of a special K-essence model, which incorporates a linear coupling term between the scalar field potential and the canonical Lagrangian. For the power law potential,…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-20 Seyed Ali Hosseini Mansoori , Hossein Moshafi

We update the search for features in the Cosmic Microwave Background (CMB) power spectrum due to transient reductions in the speed of sound, using Planck 2015 CMB temperature and polarisation data. We enlarge the parameter space to much…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-25 Jesus Torrado , Bin Hu , Ana Achucarro

The tensor-to-scalar ratio (r = 0.20^{+0.07}_{-0.05}) inferred from the excess B-mode power observed by the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) experiment is almost twice as large as the 95% CL upper limits…

High Energy Physics - Phenomenology · Physics 2015-06-19 Luis A. Anchordoqui , Haim Goldberg , Xing Huang , Brian J. Vlcek

A joint analysis of data collected by the Planck and BICEP2+Keck teams has previously given $r = 0.09^{+0.06}_{-0.04}$ for BICEP2 and $r = 0.02^{+0.04}_{-0.02}$ for Keck. Analyzing BICEP2 using its published noise estimate, we had earlier…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-24 J. Richard Gott , Wesley N. Colley

We find that the cosmic microwave background temperature and polarization power spectra measurements from Planck constrain the parameter $\Omega_bh^2$ mostly through: A) the amplitude of Thomson scattering and B) a factor that ensures…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Pavel Motloch

We present new constraints on spectator axion-${\rm U}(1)$ gauge field interactions during inflation using the latest $Planck$ (PR4) and BICEP/Keck 2018 data releases. This model can source tensor perturbations from amplified gauge field…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-03 Paolo Campeti , Ogan Özsoy , Ippei Obata , Maresuke Shiraishi

The Cosmological Principle states that the universe is statistically isotropic and homogeneous on large length scales, typically $\gtrsim 70$Mpc. A detection of significant deviation would help us falsify the simplest models of inflation.…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-26 Bhuwan Joshi , Rahul Kothari

Comparison of theobservedanisotropy with that predicted iadiabaticDM models suggest that much of thserved signal may be due to long wavelenh gravitational waves. In inflationary models this requires the generation of tensor fluctuations to…

High Energy Physics - Phenomenology · Physics 2007-05-23 Lawrence M. Krauss

We discuss the model selection problem for inflationary cosmology. We couple ModeCode, a publicly-available numerical solver for the primordial perturbation spectra, to the nested sampler MultiNest, in order to efficiently compute Bayesian…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-01 Richard Easther , Hiranya Peiris

We explore a broad class of three-parameter inflationary models, called the $\Lambda$-inflation, and its observational predictions: high abundance of cosmic gravitational waves consistent with the Harrison-Zel'dovich spectrum of primordial…

Astrophysics · Physics 2016-12-28 V. N. Lukash , E. V. Mikheeva

The advent of high-precision cosmological observations has challenged many traditional inflationary models. Data from $Planck$ 2018 along with the BICEP/$Keck$ 2018 result have already ruled out most of the established models by placing…

General Relativity and Quantum Cosmology · Physics 2026-05-27 Biswajit Deb , Atri Deshamukhya

Long-wavelength gravitational waves can induce significant temperature anisotropy in the cosmic microwave background. Distinguishing this from anisotropy induced by energy density fluctuations is critical for testing inflationary cosmology…

Astrophysics · Physics 2009-09-25 R. Crittenden , J. R. Bond , R. L. Davis , G. Efstathiou , P. J. Steinhardt

The latest Planck results show a power deficit in the temperature anisotropies near $\ell \approx 20$ in the cosmic microwave background (CMB). This observation can hardly be explained within the standard inflationary…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-05 Yi-Fu Cai , Elisa G. M. Ferreira , Bin Hu , Jerome Quintin

We present results from an analysis of all data taken by the BICEP2/Keck CMB polarization experiments up to and including the 2015 observing season. This includes the first Keck Array observations at 220 GHz and additional observations at…

In this paper we will analyze generic predictions of an inflection-point model of inflation with Hubble-induced corrections and study them in light of the Planck data. Typically inflection-point models of inflation can be embedded within…

High Energy Physics - Phenomenology · Physics 2013-07-29 Sayantan Choudhury , Anupam Mazumdar , Supratik Pal

We examine the contribution of tensor modes, in addition to the dominant scalar ones, on the temperature anisotropies of the cosmic microwave background (CMB). To this end, we analyze in detail the temperature two-point angular correlation…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-06 Miguel-Angel Sanchis-Lozano , Veronica Sanz

In the framework of inflation, scales which nowadays correspond to large scale structures were smaller than the Planck length at the beginning of inflation. Therefore, measurements of CMBR anisotropy or surveys of galaxies and of clusters…

Astrophysics · Physics 2007-05-23 Jerome Martin , Robert H. Brandenberger

We present the first attempt to use a combination of CMB, LIGO, and PPTA data to constrain both the tilt and the running of primordial tensor power spectrum through constraints on the gravitational wave energy density generated in the early…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 P. Daniel Meerburg , Renée Hložek , Boryana Hadzhiyska , Joel Meyers

The measurements of Cosmic Microwave Background anisotropies made by the Planck satellite provide extremely tight upper bounds on the total neutrino mass scale ($\Sigma m_{\nu}<0.26 eV$ at $95\%$ C.L.). However, as recently discussed in the…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-08 Eleonora Di Valentino , Alessandro Melchiorri