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The initial power spectrum of density perturbations, generated during the inflationary epoch, is now constrained by observations on scales $\lambda>5$~Mpc and has a power-law form. The peculiarities of the inflationary process can lead to…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 S. V. Pilipenko , S. A. Drozdov , M. V. Tkachev , A. G. Doroshkevich

A small deviation from scale invariance in the form of oscillations in the primordial correlation spectra has been predicted by various cosmological models. In this paper we review a recently developed method to search for these features in…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-22 P. Daniel Meerburg , David N. Spergel , Benjamin D. Wandelt

In this letter, we propose a model of inflationary cosmology with a bounce preceded and study its primordial curvature perturbations. Our model gives rise to a primordial power spectrum with a feature of oscillation on large scales compared…

Astrophysics · Physics 2009-02-02 Yi-Fu Cai , Tao-tao Qiu , Jun-Qing Xia , Xinmin Zhang

We consider Cosmic Microwave Background constraints on inflation models for which the primordial power spectrum is a mixture of perturbations generated by inflaton fluctuations and fluctuations in a curvaton field. If future experiments do…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-10 William H. Kinney , Azadeh Moradinezhad Dizgah , Antonio Riotto

Single field inflationary models that seek to greatly enhance small scale power in order to form primordial black holes predict both a squeezed bispectrum that is enhanced by this small scale power and a potentially detectable enhancement…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-08 David Zegeye , Keisuke Inomata , Wayne Hu

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

The ability to test and constrain theories of cosmic inflation will advance substantially over the next decade. Key data sources include cosmic microwave background (CMB) measurements and observations of the distribution of matter at…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-13 Benedict Bahr-Kalus , David Parkinson , Richard Easther

We constrain the spectrum of primordial curvature perturbations by using recent Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) data. Specifically, we consider CMB data from the COBE, Boomerang and Maxima experiments, the…

Astrophysics · Physics 2009-11-06 S. Hannestad , S. H. Hansen , F. L. Villante , A. J. S. Hamilton

Features in the primordial power spectrum require numerical methods that are both accurate and scalable across the wide class of multifield inflationary models that produce them. Sharp turns in the background trajectories, induced by either…

General Relativity and Quantum Cosmology · Physics 2026-03-31 Guillermo F. Quispe Peña , Johor D. Peñalba Quispitupa , José T. Gálvez Ghersi

Suppression in primordial power on the Universe's largest observable scales has been invoked as a possible explanation for large-angle observations in the cosmic microwave background, and is allowed or predicted by some inflationary models.…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-04 Cameron Gibelyou , Dragan Huterer , Wenjuan Fang

The tree order power spectra of primordial inflation depend upon the norm-squared of mode functions which oscillate for early times and then freeze in to constant values. We derive simple differential equations for the power spectra, that…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Maria G. Romania , N. C. Tsamis , R. P. Woodard

Cosmologists have embraced a particular ad hoc formula for the primordial power spectrum from inflation for universes with $\Omega_0 < 1$. However, the so-called ``Open Inflation'' models, which are attracting renewed interest in the…

High Energy Physics - Theory · Physics 2007-05-23 Michael Barnard , Andreas Albrecht

We update the constraints on possible features in the primordial inflationary density perturbation spectrum by using the latest data from the WMAP7 and ACT Cosmic Microwave Background experiments. The inclusion of new data significantly…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Micol Benetti , Massimiliano Lattanzi , Erminia Calabrese , Alessandro Melchiorri

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

Using cosmological simulations, we make predictions for the distribution of clusters in a plausible non-gaussian model where primordial voids nucleated during inflation act together with scale-invariant adiabatic gaussian fluctuations as…

Astrophysics · Physics 2009-11-07 H. Mathis , J. Silk , L. M. Griffiths , M. Kunz

We extend the work of Contaldi et al. and derive analytical approximations for primordial power spectra arising from models of inflation which include primordial spatial curvature. These analytical templates are independent of any specific…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-25 Ayngaran Thavanesan , Denis Werth , Will Handley

The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However, these results rely on the assumption of a…

Comparisons of cosmological models to current data show that the presence of a non-trivial feature in the primordial power spectrum of fluctuations, around the scale k=0.05 h/Mpc, is an open and exciting possibility, testable in a near…

High Energy Physics - Phenomenology · Physics 2009-10-31 Julien Lesgourgues

Various data analyses of the Cosmic Microwave Background (CMB) provide observational hints of statistical isotropy breaking. Some of these features can be studied within the framework of primordial vector fields in inflationary theories…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 N. Bartolo , E. Dimastrogiovanni , M. Liguori , S. Matarrese , A. Riotto

We introduce a novel framework for studying small-scale primordial perturbations and their cosmological implications. The framework uses a deep reinforcement learning to generate scalar power spectrum profiles that are consistent with…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-13 Mohit K. Sharma , M. Sami , David F. Mota