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相关论文: The CMB bispectrum from bouncing cosmologies

200 篇论文

Recent tentative findings of non-Gaussian structure in the COBE-DMR dataset have triggered renewed attention to candidate models from which such intrinsic signature could arise. In the framework of slow roll inflation with built-in non…

天体物理学 · 物理学 2009-10-31 Alejandro Gangui , Jerome Martin

We investigate the dependence of cosmological parameters on the number count of peaks (local maxima and minima) in the cosmic microwave background (CMB) sky. The peak statistics contains the whole information of acoustic oscillations in the…

天体物理学 · 物理学 2007-05-23 Toshifumi Futamase , Masahiro Takada

Recently, BICEP2 has reported the large tensor-to-scalar ratio $r=0.2^{+0.07}_{-0.05}$ from the observation of the cosmic microwave background (CMB) B-mode at degree-scales. Since tensor modes induce not only CMB B-mode but also the…

宇宙学与河外天体物理 · 物理学 2015-06-19 Masahiro Kawasaki , Shuichiro Yokoyama

We report a measurement of the E-mode polarization power spectrum of the cosmic microwave background (CMB) using 150 GHz data taken from July 2014 to December 2016 with the POLARBEAR experiment. We reach an effective polarization map noise…

We develop a new method to reconstruct the power spectrum of primordial curvature perturbations, $P(k)$, by using both the temperature and polarization spectra of the cosmic microwave background (CMB). We test this method using several mock…

天体物理学 · 物理学 2009-10-09 Noriyuki Kogo , Misao Sasaki , Jun'ichi Yokoyama

Recently, BICEP2 measurements of the cosmic microwave background (CMB) $B$-mode polarization at degree angular scales has indicated the presence of tensor modes with a high tensor-to-scalar ratio of $r=0.2$ when assuming nearly…

高能物理 - 唯象学 · 物理学 2015-06-22 Guo-Chin Liu , Kin-Wang Ng , I-Chin Wang

While the observed nearly scale-invariant initial power spectrum is regarded as one of the favorable evidence of the standard inflationary cosmology, precision observations of the Cosmic Microwave Background (CMB) anisotropies also suggest…

宇宙学与河外天体物理 · 物理学 2017-06-06 Koichiro Horiguchi , Kiyotomo Ichiki , Jun'ichi Yokoyama

We report the most complete analysis to date of observations of the Cosmic Microwave Background (CMB) obtained during the 1998 flight of BOOMERANG. We use two quite different methods to determine the angular power spectrum of the CMB in 20…

Recent results from BOOMERANG-98 and MAXIMA-1, taken together with COBE-DMR, provide consistent and high signal-to-noise measurements of the CMB power spectrum at spherical harmonic multipole bands over $2<\ell\lta800$. Analysis of the…

We analyze the spectrum of cosmic microwave background (CMB) anisotropies in the timescape cosmology: a potentially viable alternative to homogeneous isotropic cosmologies without dark energy. We exploit the fact that the timescape…

宇宙学与河外天体物理 · 物理学 2015-03-18 M. Ahsan Nazer , David L. Wiltshire

The era of precision cosmology has allowed us to accurately determine many important cosmological parameters, in particular via the CMB. Confronting Loop Quantum Cosmology with these observations provides us with a powerful test of the…

广义相对论与量子宇宙学 · 物理学 2012-04-06 Ivan Agullo , Abhay Ashtekar , William Nelson

The damping of primordial perturbations at small scales gives rise to distortions of the cosmic microwave background (CMB). Here, the dependence of the distortion on the different types of cosmological initial conditions is explored,…

宇宙学与河外天体物理 · 物理学 2014-04-18 Jens Chluba , Daniel Grin

The low quadrupole of the cosmic microwave background (CMB), measured by COBE and confirmed by WMAP, has generated much discussion recently. We point out that the well-known correlation between temperature and polarization anisotropies of…

天体物理学 · 物理学 2009-06-15 Olivier Doré , Gilbert P. Holder , Abraham Loeb

We use quadratic maximum-likelihood (QML) estimators to constrain models with Gaussian but statistically anisotropic Cosmic Microwave Background (CMB) fluctuations, using CMB maps with realistic sky-coverage and instrumental noise. This…

宇宙学与河外天体物理 · 物理学 2012-03-06 Duncan Hanson , Antony Lewis

Upcoming measurements of the small-scale primary cosmic microwave background (CMB) temperature and polarization power spectra ($TT$/$TE$/$EE$) are anticipated to yield transformative constraints on new physics, including the effective…

宇宙学与河外天体物理 · 物理学 2022-01-26 Fiona McCarthy , J. Colin Hill , Mathew S. Madhavacheril

Cosmological correlators encode rich information about physics at the Hubble scale and may exhibit characteristic oscillatory signals due to the exchange of massive particles. Although many 1-loop processes, especially those that break de…

高能物理 - 理论 · 物理学 2025-04-22 Zhehan Qin

Spectral distortions of the Cosmic Microwave Background (CMB) offer the possibility of probing processes which occurred during the evolution of our Universe going back up to Z$\simeq 10^7$. Unfortunately all the attempts so far carried out…

天体物理仪器与方法 · 物理学 2017-02-22 Giorgio Sironi

We calculate the cosmic microwave background (CMB) bispectrum due to inhomogeneous reionization. We calculate all the terms that can contribute to the bispectrum that are products of first order terms on all scales in conformal Newtonian…

宇宙学与河外天体物理 · 物理学 2014-11-20 Rishi Khatri , Benjamin D. Wandelt

This brief article sums up the possible imprints of loop quantum gravity effects on the cosmological microwave background. We focus on semi-classical terms and show that "Big Bounce" corrections, together with the "pre Big Bounce" state,…

广义相对论与量子宇宙学 · 物理学 2018-12-19 Aurelien Barrau

In light of the recent observational data coming from the sky we have two significant directions in the field of theoretical cosmology recently. First, we are now able to make use of present observations, such as the Planck and BICEP2 data,…

高能物理 - 理论 · 物理学 2014-06-19 Yi-Fu Cai