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Certain features in the primordial scalar power spectrum are known to improve the fit to the cosmological data. We examine whether bouncing scenarios can remain viable if future data confirm the presence of such features. In inflation, the…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-27 Rathul Nath Raveendran , L. Sriramkumar

In this work we explore the power of future large-scale surveys to constrain possible deviations from the standard single-field slow-roll inflationary scenario. Specifically, we parametrize possible fluctuations around the almost…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-14 Muhammad Sadegh Esmaeilian , Marzieh Farhang , Shirin Khodabakhshi

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

In this paper we break the scale invariance of the primordial power spectrum of curvature perturbations of inflation. Introducing a singular behaviour due to spontaneous symmetry breaking in the inflaton potential, we obtain fully analytic…

Astrophysics · Physics 2009-11-11 Jinn-Ouk Gong

We present primordial non-Gaussianity predictions from a new high-precision code for simulating axion-U(1) inflation on a discrete lattice. We measure the primordial scalar curvature power spectrum and bispectrum from our simulations,…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-26 Drew Jamieson , Angelo Caravano , Eiichiro Komatsu

The discovery of gravitational waves from merging binary black holes has generated considerable interest in examining whether these black holes could have a primordial origin. If a significant number of black holes have to be produced in…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-07 H. V. Ragavendra , L. Sriramkumar

Primordial black holes may arise through ultra slow-roll inflation. In this work we study a toy model of ultra slow-roll inflation with a shallow dip. The ultra slow-roll stage enhances the curvature perturbations and thus the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-02 Bao-Min Gu , Fu-Wen Shu , Ke Yang

The impact of particle production during inflation on the primordial curvature perturbation spectrum is investigated both analytically and numerically. We obtain an oscillatory behavior on small scales, while on large scales the spectrum is…

General Relativity and Quantum Cosmology · Physics 2009-02-23 Antonio Enea Romano , Misao Sasaki

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

[Abridged] The primordial scalar power spectrum is well constrained on large scales, primarily by the observations of the anisotropies in the cosmic microwave background (CMB). Over the last few years, it has been recognized that a sharp…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 H. V. Ragavendra , Pankaj Saha , L. Sriramkumar , Joseph Silk

We propose a novel enhancement mechanism of the curvature perturbations in the nonminimal derivative coupling inflation model with a coupling parameter related to the inflaton field. By considering a special form of the coupling parameter…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-26 Chengjie Fu , Puxun Wu , Hongwei Yu

The next generation of cosmological observations will be sensitive to small deviations from a pure power law in the primordial power spectrum of the curvature perturbations. In the context of slow-roll inflation, these deviations are…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-15 Pierre Auclair , Christophe Ringeval

The detection of a primordial stochastic gravitational wave background has the potential to reveal unprecedented insights into the early universe, and possibly into the dynamics of inflation. Generically, UV-complete inflationary models…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-08 Vikas Aragam , Sonia Paban , Robert Rosati

Perturbations from inflation evolve into large scale structure of the late universe, and encode abundant cosmic structure formation physics. We allow freedom in the primordial power spectrum, rather than assuming a power law scale…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-12 Guilherme Brando , Eric V. Linder

Future cosmic microwave background polarization experiments will search for evidence of primordial tensor modes at large angular scales, in the multipole range $4 \leq \ell \leq 50.$ Because in that range there is some mild evidence of…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-26 Gonzalo A. Palma , Bastian Pradenas , Walter Riquelme , Spyros Sypsas

A short inflationary phase may not erase all traces of the primordial universe. Associated observables include both spatial curvature and "anomalies" in the microwave background or large scale structure. The present curvature $\Omega_{K,0}$…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-25 Grigor Aslanyan , Richard Easther

We study the generation of sharp features in the primordial spectra within the framework of effective field theory of inflation, wherein curvature perturbations are the consequence of the dynamics of a single scalar degree of freedom. We…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-29 Sander Mooij , Gonzalo A. Palma , Grigoris Panotopoulos , Alex Soto

We investigate two classes of inflationary models, which lead to a stiff period after inflation that boosts the signal of primordial gravitational waves (GWs). In both families of models studied, we consider an oscillating scalar…

High Energy Physics - Phenomenology · Physics 2024-10-10 Chao Chen , Konstantinos Dimopoulos , Cem Eröncel , Anish Ghoshal

The inflationary and pre-inflationary evolution of scalar modes of cosmological perturbations in a closed universe is analyzed for a loop quantum cosmology model with an inflationary regime consistent with the constraints on inflation…

General Relativity and Quantum Cosmology · Physics 2024-11-26 Lucas M. V. Montese , Nelson Yokomizo

We discuss the possible existence of features in both the primordial power spectrum and bispectrum generated during a stage of single field cosmic inflation. We argue that there are two main classes of features: those produced by a sudden…

High Energy Physics - Theory · Physics 2015-06-23 Gonzalo A. Palma