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We consider a scenario in which primordial scalar perturbations are generated when complex conformal scalar field rolls down its negative quartic potential. Initially, these are the perturbations of the phase of this field; they are…

High Energy Physics - Theory · Physics 2010-12-06 M. Libanov , V. Rubakov

The corrections to the cosmological models induced by non-minimal coupling between scalar field and torsion are considered. To determine these corrections in explicit form, the power-law parametrization of these corrections are proposed.…

General Relativity and Quantum Cosmology · Physics 2025-03-25 I. V. Fomin , S. V. Chervon , L. K. Duchaniya , B. Mishra

We describe an attempt to reconstruct the initial conditions for the formation of cosmological large-scale structure. The power spectrum of the primordial fluctuations is affected by bias, nonlinear evolution and redshift-space distortions,…

Astrophysics · Physics 2015-06-24 J. A. Peacock , S. J. Dodds

During the last years it has become clear that global O(N) defects and U(1) cosmic strings do not lead to the pronounced first acoustic peak in the power spectrum of anisotropies of the cosmic microwave background which has recently been…

Astrophysics · Physics 2008-11-26 R. Durrer , M. Kunz , A. Melchiorri

The primordial magnetic field (PMF) can strongly affect the cosmic microwave background (CMB) power spectrum and the formation of large scale structure. In this presentation, we calculate the CMB temperature anisotropies generated by…

Astrophysics · Physics 2008-11-26 Dai G. Yamazaki , Kiyotomo Ichiki , Toshitaka Kajino , Grant J. Mathews

The nearly scale-invariant primordial power spectrum provides the standard initial conditions for cosmological perturbations. However, the largest scales remain only weakly constrained by CMB observations, leaving room for deviations such…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-19 Ujjwal Upadhyay , Yashi Tiwari , Tarun Souradeep

We study the asymmetric primordial fluctuations in a model of inflation in which translational invariance is broken by a domain wall. We calculate the corrections to the power spectrum of curvature perturbations; they are anisotropic and…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-02 Sadra Jazayeri , Yashar Akrami , Hassan Firouzjahi , Adam R. Solomon , Yi Wang

In inflationary models with minimal amount of gravity waves, the primordial power spectrum of density fluctuations, $A_S^2(k)$, together with the basic cosmological parameters, completely specify the predictions for the cosmic microwave…

Astrophysics · Physics 2009-10-31 Yun Wang , David N. Spergel , Michael A. Strauss

Inflationary models predicting a scale-dependent large amplification of the density perturbations have recently attracted a lot of attention because the amplified perturbations can seed a sizable amount of primordial black holes (PBHs) and…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-28 Keisuke Inomata , Matteo Braglia , Xingang Chen , Sébastien Renaux-Petel

We investigate scale-dependent modifications to the primordial scalar power spectrum as potential solutions to the Hubble tension. We use the Fisher-bias formalism, recently adapted to examine perturbed recombination solutions to the Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-13 Nanoom Lee , Matteo Braglia , Yacine Ali-Haïmoud

Certain oscillatory features in the primordial scalar power spectrum are known to provide a better fit to the outliers in the cosmic microwave background data near the multipole moments of $\ell=22$ and 40. These features are usually…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Dhiraj Kumar Hazra , Moumita Aich , Rajeev Kumar Jain , L. Sriramkumar , Tarun Souradeep

We discuss whether an unaccounted contribution to the Cosmic Microwave Background polarization $B$-mode by primordial magnetic fields (PMFs) can bias future constraints on inflationary gravitational waves. As a case-study, we consider a…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-05 Fabrizio Renzi , Giovanni Cabass , Eleonora Di Valentino , Alessandro Melchiorri , Luca Pagano

Thermal inflation is a second epoch of exponential expansion at typical energy scales $V^{1/4} \sim 10^{6 \sim 8} \mathrm{GeV}$. If the usual primordial inflation is followed by thermal inflation, the primordial power spectrum is only…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-09 Kihyun Cho , Sungwook E. Hong , Ewan D. Stewart , Heeseung Zoe

Forthcoming CMB experiments will allow us to accurately investigate the power spectrum at very small scales ($\ell > 1000$). We predict the level of the primary anisotropies, given the actual CMB measurements. The secondary anisotropies…

Astrophysics · Physics 2009-11-07 N. Aghanim , P. G. Castro , A. Melchiorri , J. Silk

We study the implications of deformed quantum algebras for the generation of primordial perturbations from slow-roll inflation. Specifically, we assume that the quantum commutator of the inflaton's amplitude and momentum in Fourier space…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Andrew C. Day , Iain A. Brown , Sanjeev S. Seahra

Using the temperature data from Planck we search for departures from a power-law primordial power spectrum, employing Bayesian model-selection and posterior probabilities. We parametrize the spectrum with $n$ knots located at arbitrary…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-28 Grigor Aslanyan , Layne C. Price , Kevork N. Abazajian , Richard Easther

The primordial power spectrum of curvature perturbations has been well-measured on large scales but remains fairly unconstrained at smaller scales, where significant deviations from $\Lambda$CDM may occur. Measurements of 21-cm intensity…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-14 Jessie de Kruijf , Eleonora Vanzan , Kimberly K. Boddy , Alvise Raccanelli , Nicola Bartolo

We continue the study of mild transient reductions in the speed of sound of the adiabatic mode during inflation, of their effect on the primordial power spectrum and bispectrum, and of their detectability in the Cosmic Microwave Background…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-19 Ana Achucarro , Vicente Atal , Bin Hu , Pablo Ortiz , Jesus Torrado

Second-order power spectra of Cosmic Microwave Background (CMB) anisotropies due to random primordial perturbations at the matter dominant stage are studied, based on the relativistic second-order theory of perturbations in flat…

Astrophysics · Physics 2008-11-26 Kenji Tomita

We observationally examine cosmological models based on primordial power spectra with quantized wavevectors. Introducing a linearly quantized power spectrum with $k_0=3.225\times10^{-4}\mathrm{Mpc}^{-1}$ and spacing $\Delta k = 2.257 \times…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-18 D. J. Bartlett , W. J. Handley , A. N. Lasenby
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