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%The content of this replacement paper is identical to the original. %We have attempted to fix the postscript so that it will print out on %a larger number of printers. Using recent experimental limits on $\mu$ distortions from COBE FIRAS,…

Astrophysics · Physics 2009-10-22 Wayne Hu , Douglas Scott , Joseph Silk

We investigate inflationary scenarios driven by a class of potentials which are similar in form to those that arise in certain minimal supersymmetric extensions of the standard model. We find that these potentials allow a brief period of…

Recent observations of the cosmic microwave background (CMB) anisotropies and the distribution of galaxies, galaxy clusters, and the Lyman Alpha forest have constrained the shape of the power spectrum of matter fluctuations on large scales…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Aravind Natarajan , Nick Zhu , Naoki Yoshida

Bursts of particle production during inflation provide a well-motivated mechanism for creating bump like features in the primordial power spectrum. Current data constrains these features to be less than about 5% the size of the featureless…

Cosmology and Nongalactic Astrophysics · Physics 2011-05-12 Teeraparb Chantavat , Christopher Gordon , Joseph Silk

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

We extend an alternative, phenomenological approach to inflation by means of an equation of state and a sound speed, both of them functions of the number of $e$-folds and four phenomenological parameters. This approach captures a number of…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-10 Stefano Gariazzo , Olga Mena , Hector Ramirez , Lotfi Boubekeur

In this work we constrain the bounce energy scale $\rho_{s\downarrow}^{1/4}$ in a generic framework of bouncing cosmologies using the nanohertz stochastic gravitational-wave background recently detected by pulsar timing arrays (NANOGrav…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-09 Junrong Lai , Changhong Li

The current suite of results from Cosmic Microwave Background anisotropy experiments is fulfilling the promise of providing extraordinary levels of discrimination between cosmological models. We calculate a binned anisotropy power spectrum,…

Astrophysics · Physics 2007-05-23 Elena Pierpaoli , Douglas Scott , Martin White

We propose the gravity's rainbow scenario as a possible alternative of the inflation paradigm to account for the flatness and horizon problems. We focus on studying the cosmological scalar perturbations which are seeded by the quantum…

General Relativity and Quantum Cosmology · Physics 2015-05-15 Sai Wang , Zhe Chang

We analyse the efficiency of future large scale structure surveys to unveil the presence of scale dependent features in the primordial spectrum --resulting from cosmic inflation-- imprinted in the distribution of galaxies. Features may…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-04 Gonzalo A. Palma , Domenico Sapone , Spyros Sypsas

The anisotropy of the cosmic microwave background radiation contains information about the contents and history of the universe. We report new limits on cosmological parameters derived from the angular power spectrum measured in the first…

We investigate the bounce realization in the framework of DHOST cosmology, focusing on the relation with observables. We perform a detailed analysis of the scalar and tensor perturbations during the Ekpyrotic contraction phase, the bounce…

General Relativity and Quantum Cosmology · Physics 2021-11-24 Mian Zhu , Amara Ilyas , Yunlong Zheng , Yi-Fu Cai , Emmanuel N. Saridakis

We perform a cosmological analysis in which we allow the primordial power spectrum of scalar perturbations to assume a shape that is different with respect to the usual power-law, arising from the simplest models of cosmological inflation.…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-22 Stefano Gariazzo

The observational constraints on the primordial power spectrum have tightened considerably with the release of the first year analysis of the WMAP observations, especially when combined with the results from other CMB experiments and galaxy…

High Energy Physics - Phenomenology · Physics 2009-11-10 Dominik J. Schwarz , Cesar A. Terrero-Escalante

Observed power spectrum of matter found in Papers I and II is compared with analytical power spectra. Spatially flat cold and mixed dark matter models with cosmological constant and open models are considered. The primordial power spectrum…

Astrophysics · Physics 2009-10-31 J. Einasto , M. Einasto , E. Tago , A. A. Starobinsky , F. Atrio-Barandela , V. M"uller , A. Knebe , R. Cen

We extend to large scales a method proposed in previous work that reconstructs non-parametrically the primordial power spectrum from cosmic microwave background data at high resolution. The improvement is necessary to account for the…

Astrophysics · Physics 2009-11-13 Domenico Tocchini-Valentini , Yehuda Hoffman , Joseph Silk

The combined analysis of the cosmic microwave background on large scales and Lyman-alpha forest on small scales provides a sufficiently long lever arm to obtain strong constraints on the slope and curvature of the power spectrum of…

Astrophysics · Physics 2009-11-10 Matteo Viel , Jochen Weller , Martin Haehnelt

It is shown that teleparallel $F(T)$ theories of gravity combined with holonomy corrected Loop Quantum Cosmology (LQC) support a Matter Bounce Scenario (MBS) which is a potential alternative to the inflationary paradigm. The Matter Bounce…

General Relativity and Quantum Cosmology · Physics 2015-01-27 Jaume Haro , Jaume Amorós

We study the predictions of anomalous inflationary models on the abundance of structures in large scale structure observations. The anomalous features encoded in primordial curvature perturbation power spectrum are (a): localized feature in…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-30 Shant Baghram , Ali Akbar Abolhasani , Hassan Firouzjahi , Mohammad Hossein Namjoo

If the spatial sections of the Universe are positively curved, extrapolating the inflationary stage backward in time inevitably leads to a classical bounce. This simple scenario, non-singular and free of exotic physics, deserves to be…

General Relativity and Quantum Cosmology · Physics 2022-09-21 Cyril Renevey , Aurélien Barrau , Killian Martineau
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