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We revisit an inflationary scenario in which primordial inhomogeneities arise from a quantum collapse, a stochastic mechanism described in the context of quantum collapse theories in its continuous version and within semiclassical gravity.…

General Relativity and Quantum Cosmology · Physics 2026-03-04 María Pía Piccirilli , Gabriel León , Rosa-Laura Lechuga-Solis , Daniel Sudarsky

We consider a class of inflationary models with small oscillations imprinted on an otherwise smooth inflaton potential. These oscillations are manifest as oscillations in the power spectrum of primordial perturbations, which then give rise…

Astrophysics · Physics 2009-11-13 Cédric Pahud , Marc Kamionkowski , Andrew R Liddle

We study features in the bispectrum of the primordial curvature perturbation correlated with the reconstructed primordial power spectrum from the observed cosmic microwave background temperature data. We first show how the bispectrum can be…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-25 Stephen Appleby , Jinn-Ouk Gong , Dhiraj Kumar Hazra , Arman Shafieloo , Spyros Sypsas

We present a Bayesian analysis of large-scale structure and cosmic microwave background data to constrain the form of the primordial power spectrum. We have extended the usual presumption of a scale invariant spectrum to include: (i) a…

Astrophysics · Physics 2009-11-11 M. Bridges , A. N. Lasenby , M. P. Hobson

We consider the prospects of probing features in the primordial power spectrum with future Cosmic Microwave Background (CMB) polarization measurements. In the scope of the inflationary scenario, such features in the spectrum can be produced…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-05 Dhiraj Kumar Hazra , Daniela Paoletti , Mario Ballardini , Fabio Finelli , Arman Shafieloo , George F. Smoot , Alexei A. Starobinsky

We identify examples of single field inflationary trajectories beyond the slow-roll regime which improve the fit to Planck 2018 data compared to baseline $\Lambda$CDM model with power law form of primordial spectrum and at the same time…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-05 Akhil Antony , Fabio Finelli , Dhiraj Kumar Hazra , Arman Shafieloo

In the ``natural inflation'' model, the inflaton potential is periodic. We show that Planck scale physics may induce corrections to the inflaton potential, which is also periodic with a greater frequency. Such high frequency corrections…

Astrophysics · Physics 2008-11-26 Xiulian Wang , Bo Feng , Mingzhe Li , Xue-Lei Chen , Xinmin Zhang

We investigate the prospects and consequences of the spectral level reconstruction of primordial $B$-mode power by solving the systems of linear equations assuming that the lensing potential together with the lensed polarization spectra are…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-10 Barun Pal

The constraints on a general form of the power-law potential and the dissipation coefficient in the framework of warm single field inflation imposed by Planck data will be investigated. {By Considering a quasi-static Universe, besides a…

General Relativity and Quantum Cosmology · Physics 2019-12-03 Zahra Ghadiri , Abdollah Refaei , Ali Aghamohammadi , Haidar Sheikhahmadi

We reconstruct the shape of the primordial power spectrum (PPS) using a smoothing spline. Our adapted smoothing spline technique provides a complementary method to existing efforts to search for smooth features in the PPS, such as a running…

Astrophysics · Physics 2009-11-13 Carolyn Sealfon , Licia Verde , Raul Jimenez

Future astrophysical datasets promise to strengthen constraints on models of inflation, and extracting these constraints requires methods and tools commensurate with the quality of the data. In this paper we describe ModeCode, a new,…

Cosmology and Nongalactic Astrophysics · Physics 2011-02-10 Michael J. Mortonson , Hiranya V. Peiris , Richard Easther

Standard CMB analysis assumes a direct deterministic mapping between the multipole probed by the CMB $\ell$ and the primordial wavenumber $k$. Since the recombination era has a finite duration, this mapping is probabilistic by construction.…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-20 V. K. Oikonomou

We study inflation within the framework of non-canonical scalar field. In this scenario, we obtain the inflationary observables such as the scalar spectral index, the tensor-to-scalar ratio, the running of the scalar spectral index as well…

General Relativity and Quantum Cosmology · Physics 2017-05-31 Zeinab Teimoori , Kayoomars Karami

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

While the observed nearly scale-invariant initial power spectrum is regarded as one of the favorable evidence of the standard inflationary cosmology, precision observations of the Cosmic Microwave Background (CMB) anisotropies also suggest…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-06 Koichiro Horiguchi , Kiyotomo Ichiki , Jun'ichi Yokoyama

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

The simplest models of inflation predict small non-gaussianities and a featureless power spectrum. However, there exist a large number of well-motivated theoretical scenarios in which large non-gaussianties could be generated. In general,…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-11 Stefano Gariazzo , Laura Lopez-Honorez , Olga Mena

Sudden violations of the slow-roll regime during inflation, a natural prediction of many UV-complete inflationary models, give rise to sharp features in the primordial power spectrum. At large scales, these features provide a unique window…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-05 Clément Stahl , Denis Werth , Vivian Poulin

We revisit the problem of constraining steps in the inflationary potential with cosmological data. We argue that a step in the inflationary potential produces qualitatively similar oscillations in the primordial power spectrum,…

Astrophysics · Physics 2008-11-26 Jan Hamann , Laura Covi , Alessandro Melchiorri , Anze Slosar

Non-parametric reconstruction or marginalization over the history of reionization using cosmic microwave background data necessarily assumes a prior over possible histories. We show that different but reasonable choices of priors can shift…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-03 Marius Millea , François Bouchet