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We investigate constraints on power spectra of the primordial curvature and tensor perturbations with priors based on single-field slow-roll inflation models. We stochastically draw the Hubble slow-roll parameters and generate the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Masahiro Kawasaki , Toyokazu Sekiguchi

We investigate the constraints on primordial non-Gaussianity with varied bispectrum shapes that can be derived from the power spectrum of galaxies and clusters of galaxies detected in future wide field optical/near-infrared surveys. Having…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Cosimo Fedeli , Carmelita Carbone , Lauro Moscardini , Andrea Cimatti

The BICEP-2 team has reported the detection of primordial cosmic microwave background B-mode polarization, with hints of a suppression of power at large angular scales relative to smaller scales. Provided that the B-mode polarization is due…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-01 Robert H. Brandenberger , Ali Nayeri , Subodh P. Patil

The small-scale crisis, discrepancies between observations and N-body simulations, may imply suppressed matter fluctuations on subgalactic distance scales. Such a suppression could be caused by some early-universe mechanism (e.g., broken…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-05 Tomohiro Nakama , Jens Chluba , Marc Kamionkowski

In inflationary cosmology, the form of the potential is still an open problem. In this work, second-order effects of the inflationary potential are evaluated and related to the known formula for the primordial perturbations at a wide range…

General Relativity and Quantum Cosmology · Physics 2024-11-01 Paulo Custodio , Cristian R. Ghezzi , Nadja S. Magalhae , Carlos Frajuca

We study the generation of density perturbations in the ekpyrotic scenario for the early universe, including gravitational backreaction. We expose interesting subtleties that apply to both inflationary and ekpyrotic models. Our analysis…

High Energy Physics - Theory · Physics 2009-09-15 Justin Khoury , Burt A. Ovrut , Paul J. Steinhardt , Neil Turok

We study the preheating of gauge fields in a simple axion monodromy model and compute the induced entropy perturbations and their effect on the curvature fluctuations. We find that the correction to the spectrum of curvature perturbations…

High Energy Physics - Theory · Physics 2016-05-25 Evan McDonough , Hossein Bazrafshan Moghaddam , Robert H. Brandenberger

Beyond existing multi-view clustering, this paper studies a more realistic clustering scenario, referred to as incomplete multi-view clustering, where a number of data instances are missing in certain views. To tackle this problem, we…

Machine Learning · Computer Science 2019-06-04 Hao Wang , Linlin Zong , Bing Liu , Yan Yang , Wei Zhou

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

We investigate primordial non-Gaussianity and dark matter isocurvature fluctuations in the modulated reheating and the curvaton scenarios. In these scenarios, large non-Gaussianity can be generated, on the other hand, depending on how dark…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Tomo Takahashi , Masahide Yamaguchi , Shuichiro Yokoyama

Recent cosmological observations, including measurements of the CMB anisotropy and the primordial helium abundance, indicate the existence of an extra radiation component in the Universe beyond the standard three neutrino species. In this…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Masahiro Kawasaki , Koichi Miyamoto , Kazunori Nakayama , Toyokazu Sekiguchi

Primordial black holes may form in the early Universe, for example from the collapse of large amplitude density perturbations predicted in some inflationary models. Light black holes undergo Hawking evaporation, the energy injection from…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Andrew R Liddle , Anne M Green

We have investigated the effect of the number of primordial binaries on the relationship between the total number of detected binaries within globular cluster and its collision rate. We have used simulated populations of binary stars in…

Astrophysics · Physics 2009-11-10 B. Gendre

We present proof of principle for a two way interplay between physics at very early Universe and late time observations. We find a relation between primordial mechanisms responsible for large scale power suppression in the primordial power…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-04 Brajesh Gupt

We examine a type of features in the primordial scalar power spectrum, namely, the bump-like feature(s) that arise as a result of burst(s) of particle production during inflation. The latest CMB observations by Planck 2018 can accommodate…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-07 Suvedha Suresh Naik , Pravabati Chingangbam , Kazuyuki Furuuchi

We provide a generic but physically clear discussion of the clustering properties of dark energy models. We explicitly show that in quintessence-type models the dark energy fluctuations, on scales smaller than the Hubble radius, are of the…

Astrophysics · Physics 2008-11-26 P. P. Avelino , L. M. G. Beca , C. J. A. P. Martins

We discuss the leading particle spectra and diffractive mass spectra from the novel point of view, namely by treating them as particular examples of the general energy flow phenomena taking place in the multiparticle production processes.…

High Energy Physics - Phenomenology · Physics 2007-05-23 F. O. Duraes , F. S. Navarra , G. Wilk

In the standard slow-roll inflationary cosmology, quantum fluctuations in a single field, the inflaton, generate approximately Gaussian primordial density perturbations. At present, the bispectrum and trispectrum of the density…

High Energy Physics - Phenomenology · Physics 2010-08-03 Kevin T. Engel , Keith S. M. Lee , Mark B. Wise

Models for structure formation attempt to predict the power spectrum of density perturbations in the present universe from the initial power spectrum and the nature of dark matter. Observational constraints on the power spectrum at…

Astrophysics · Physics 2007-05-23 K. Subramanian , T. Padmanabhan

In this paper, we suppose that the universe begins in a holographic thermal equilibrium phase with the diverged correlation length, and the phase transition to the radiation phase of standard cosmology goes with the abrupt reducing of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Yun-Song Piao
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