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Related papers: Optimal Binning of the Primordial Power Spectrum

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We study the generation and evolution of second-order energy-density perturbations arising from primordial gravitational waves. Such "tensor-induced scalar modes" approximately evolve as standard linear matter perturbations and may leave…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-30 Pritha Bari , Angelo Ricciardone , Nicola Bartolo , Daniele Bertacca , Sabino Matarrese

Inflation may provide unique insight into the physics at the highest available energy scales that cannot be replicated in any realistic terrestrial experiment. Features in the primordial power spectrum are generically predicted in a wide…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-26 Anže Slosar , Xingang Chen , Cora Dvorkin , Daniel Green , P. Daniel Meerburg , Eva Silverstein , Benjamin Wallisch

Inflationary cosmology with a preceding nonsingular bounce can lead to changes on the primordial density fluctuations. One significant prediction is that the amplitude of the power spectrum may undergo a jump at a critical scale. In this…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-10 Jie Liu , Yi-Fu Cai , Hong Li

We have developed a precise dictionary between the spectrum of primordial density fluctuations and the parameters of the effective field theory (EFT) of inflation that determine the primordial power spectrum (PPS). At lowest order the EFT…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-15 Amel Durakovic

Magnetic fields are everywhere in nature and they play an important role in every astronomical environment which involves the formation of plasma and currents. It is natural therefore to suppose that magnetic fields could be present in the…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-22 Dai G. Yamazaki , Kiyotomo Ichiki , Toshitaka Kajino , Grant J. Mathew

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

In this first of two papers, we present a new method for searching for oscillatory features in the primordial power spectrum. A wide variety of models predict these features in one of two different flavors: logarithmically spaced…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-02 P. Daniel Meerburg , David N. Spergel , Benjamin D. Wandelt

In inflationary models with minimal amount of gravity waves, the primordial power spectrum of density fluctuations, $A_S^2(k)$, together with the basic cosmological parameters, completely specify the predictions for the cosmic microwave…

Astrophysics · Physics 2009-10-31 Yun Wang , David N. Spergel , Michael A. Strauss

We investigate how well galaxy cluster number counts can constrain the primordial power spectrum. Measurements of the primary anisotropies in the cosmic microwave background (CMB) may be limited, by the presence of foregrounds from…

Astrophysics · Physics 2015-03-13 Teeraparb Chantavat , Christopher Gordon , Joseph Silk

Magnetic fields appear wherever plasma and currents can be found. As such, they thread through all scales in Nature. It is natural, therefore, to suppose that magnetic fields might have been formed within the high temperature environments…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-16 Dai G. Yamazaki , Toshitaka Kajino , Grant J. Mathew , Kiyotomo Ichiki

Detecting a deviation from a featureless primordial power spectrum of fluctuations would give profound insight into the physics of the primordial Universe. Depending on their nature, primordial features can either provide direct evidence…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-28 Xingang Chen , P. Daniel Meerburg , Moritz Münchmeyer

Pursuing the original idea proposed in our previous paper (Paper I), we improve the method to determine the shape of the initial curvature perturbation spectrum $P(k)$ from the CMB data. The thickness of the last scattering surface (LSS)…

Astrophysics · Physics 2009-10-09 Makoto Matsumiya , Misao Sasaki , Jun'ichi Yokoyama

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 present the newest statistical and numerical analysis of the matter and cosmic microwave background power spectrum with effects of the primordial magnetic field (PMF) included. New limits to the PMF strength and power spectral index are…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Dai G. Yamazaki , Kiyotomo Ichiki , Toshitaka Kajino , Grant. J. Mathews

We exploit a new numerical technique for evaluating the tree order contributions to the primordial scalar and tensor power spectra for scalar potential models of inflation. Among other things we use the formalism to develop a good analytic…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-06 D. J. Brooker , N. C. Tsamis , R. P. Woodard

We reconstruct the power spectrum of primordial curvature perturbations by applying a well-validated non-parametric technique employing Tikhonov regularisation to the first data release from the Planck satellite. To improve the…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-31 Paul Hunt , Subir Sarkar

Constraints on the main cosmological parameters using CMB or large scale structure data are usually based on power-law assumption of the primordial power spectrum (PPS). However, in the absence of a preferred model for the early universe,…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-14 Dhiraj Kumar Hazra , Arman Shafieloo , Tarun Souradeep

The basic cosmological parameters and the primordial power spectrum together completely specify predictions for the cosmic microwave background radiation anisotropy and large scale structure. Here we show how we can strongly constrain both…

Astrophysics · Physics 2010-11-30 Yun Wang , David N. Spergel , Michael A. Strauss

Experimentally distinguishing different primordial universe paradigms that lead to the Big Bang model is an outstanding challenge in modern cosmology and astrophysics. We show that a generic type of signals that exist in primordial universe…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Xingang Chen

The appearance of peaks in various primordial fluctuation Fourier power spectra is a generic prediction of the inflationary scenario. We investigate whether future experiments, in particular the satellite experiment PLANCK, will be able to…

General Relativity and Quantum Cosmology · Physics 2009-08-11 J. Lesgourgues , D. Polarski , S. Prunet , A. A. Starobinsky