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We describe an attempt to reconstruct the initial conditions for the formation of cosmological large-scale structure. The power spectrum of the primordial fluctuations is affected by bias, nonlinear evolution and redshift-space distortions,…

Astrophysics · Physics 2015-06-24 J. A. Peacock , S. J. Dodds

We review the relevant 10+ parameters associated with inflation and matter content; the relation between LSS and primary and secondary CMB anisotropy probes; COBE constraints on energy injection; current anisotropy band-powers which…

Astrophysics · Physics 2009-10-30 J. Richard Bond , Andrew H. Jaffe

A stochastic background of primordial gravitational waves could be detected soon in the polarization of the CMB and/or with laser interferometers. There are at least three GWB coming from inflation: those produced during inflation and…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-11 Juan Garcia-Bellido

We investigate the possibility that fields coupled to the inflaton can influence the primordial spectrum of density perturbations through their coherent motion. For example, the second field in hybrid inflation might be oscillating at the…

Astrophysics · Physics 2008-11-26 J. M. Cline

Recent released WMAP data show a low value of quadrupole in the CMB temperature fluctuations, which confirms the early observations by COBE. In this paper we consider a model of two inflatons with different masses, $V(\phi_1,\phi_2)={1\over…

Astrophysics · Physics 2009-11-07 Bo Feng , Xinmin Zhang

Primordial non-Gaussianity arising from inflationary models is a unique probe of non-trivial dynamics of the inflaton field and its interactions with other fields. Often when examining and constraining the scalar non-Gaussianity arising…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-17 Barnali Das , H. V. Ragavendra

The decoherence of quantum fluctuations into classical perturbations during inflation is discussed. A simple quantum mechanical argument, using a spatial particle wavefunction rather than a field description, shows that observable…

Astrophysics · Physics 2007-05-23 Craig J. Hogan

We investigate the degree to which the Cosmic Microwave Background (CMB) can be used to constrain primordial non-Gaussianity coming from the presence of spinning particles coupled to the inflaton. We compute the $\langle TTT \rangle$ and…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-09 Lorenzo Bordin , Giovanni Cabass

We explore a plausible mechanism that the hemispherical power asymmetry in the CMB is produced by the spatial variation of the primordial sound speed parameter. We suggest that in a generalized approach of the $\delta N$ formalism the local…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-11 Dong-Gang Wang , Yi-Fu Cai , Wen Zhao , Yang Zhang

Gaussianity and statistical isotropy of the Universe are modern cosmology's minimal set of hypotheses. In this work we introduce a new statistical test to detect observational deviations from this minimal set. By defining the temperature…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-30 Thiago S. Pereira , L. Raul Abramo

Inflationary cosmologies predict Gaussian primordial fluctuations, but subsequent gravitational lensing of the CMB disturbs its Gaussianity. Knowledge of the specific signature of lensing is necessary to distinguish a lensed Gaussian sky…

Astrophysics · Physics 2007-05-23 Serge Winitzki

We examine stochastic temperature fluctuations of the cosmic background radiation (CBR) arising via the Sachs-Wolfe effect from gravitational wave perturbations produced in the early universe. These temperature fluctuations are described by…

Astrophysics · Physics 2009-10-22 Bruce Allen , Scott Koranda

Thermal fluctuations provide the main source of large scale density perturbations in warm inflationary models of the early universe. For the first time, general results are obtained for the power spectrum in the case when the friction…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-28 Chris Graham , Ian G Moss

The generic prediction for the perturbations generated during slow--roll, single--field inflation, as they appear in the cosmic microwave background (CMB), is a flat, close--to--Gaussian spectrum. We calculate the general solution for a…

Astrophysics · Physics 2007-05-23 S. Gupta

Causal seed models, such as cosmological defects, generically predict a distinctly different structure to the CMB power spectrum than inflation, due to the behavior of the perturbations outside the horizon. We provide a general analysis of…

Astrophysics · Physics 2009-08-18 Wayne Hu , David N. Spergel , Martin White

We reevaluate the predictions of inflation regarding primordial gravity waves, which should appear as B-modes in the CMB, in light of the fact that the standard inflationary paradigm is unable to account for the transition from an initially…

General Relativity and Quantum Cosmology · Physics 2017-11-22 Gabriel León , Abhishek Majhi , Elias Okon , Daniel Sudarsky

The emergence of several unexpected large-scale features in the cosmic microwave background (CMB) has pointed to possible new physics driving the origin of density fluctuations in the early Universe and their evolution into the large-scale…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-26 Fulvio Melia

If the hemispherical power asymmetry observed in the cosmic microwave background (CMB) on large angular scales is attributable to a superhorizon curvaton fluctuation, then the simplest model predicts that the primordial density fluctuations…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Adrienne L. Erickcek , Christopher M. Hirata , Marc Kamionkowski

Thermal inflation is a second epoch of exponential expansion at typical energy scales $V^{1/4} \sim 10^{6 \sim 8} \mathrm{GeV}$. If the usual primordial inflation is followed by thermal inflation, the primordial power spectrum is only…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-09 Kihyun Cho , Sungwook E. Hong , Ewan D. Stewart , Heeseung Zoe

We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear $\delta…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Hooshyar Assadullahi , Hassan Firouzjahi , Mohammad Hossein Namjoo , David Wands