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The cosmic microwave background (CMB) contains perturbations that are close to Gaussian and isotropic. This means that its information content, in the sense of the ability to constrain cosmological models, is closely related to the number…

宇宙学与河外天体物理 · 物理学 2016-07-06 Douglas Scott , Dagoberto Contreras , Ali Narimani , Yin-Zhe Ma

If inflation was preceded by a radiation era then at the time of inflation there will exist a decoupled thermal distribution of gravitons. Gravitational waves generated during inflation will be amplified by the process of stimulated…

天体物理学 · 物理学 2008-11-26 Kaushik Bhattacharya , Subhendra Mohanty , Akhilesh Nautiyal

We study the effect of Faraday rotation due to a homogeneous magnetic field on the polarization of the cosmic microwave background (CMB). Scalar fluctuations give rise only to parity-even E-type polarization of the CMB. However in the…

天体物理学 · 物理学 2009-11-10 Claudia Scoccola , Diego Harari , Silvia Mollerach

We investigate the observational signatures of three models of the early Universe in the $B$-mode polarization of the Cosmic Microwave Background (CMB) radiation. In addition to the standard single field inflationary model, we also consider…

宇宙学与河外天体物理 · 物理学 2011-01-27 Yin-Zhe Ma , Wen Zhao , Michael L. Brown

B-modes of Cosmic Microwave Background (CMB) polarization can be created by a primordial gravitational wave background. If this background was created by Inflation, then the amplitude of the polarization signal is proportional the energy…

天体物理学 · 物理学 2008-11-26 Alexandre Amblard , Asantha Cooray , Manoj Kaplinghat

Using only cosmic microwave background polarization data from the POLARBEAR experiment, we measure $B$-mode polarization delensing on subdegree scales at more than $5\sigma$ significance. We achieve a 14% $B$-mode power variance reduction,…

Measurements of the cosmic microwave background (CMB) temperature anisotropies have revealed a dipolar asymmetry in power at the largest scales, in apparent contradiction with the statistical isotropy of standard cosmological models. The…

宇宙学与河外天体物理 · 物理学 2018-03-07 D. Contreras , J. Hutchinson , A. Moss , D. Scott , J. P. Zibin

BICEP2's detection on the primordial B-mode of CMB polarization suggests that inflation occurred around GUT scale, with the tensor-to-scalar ratio r~0.2. Inspired by this discosvery, we study the topological inflation which was driven by a…

宇宙学与河外天体物理 · 物理学 2014-07-15 Yu-Chieh Chung , Chunshan Lin

The recent detection by the BICEP2 collaboration of a high level of tensor modes has relevant implications which we briefly discuss in this short note. In particular, the large angle CMB B- mode polarisation seems to imply problematic…

宇宙学与河外天体物理 · 物理学 2014-05-28 Alex Kehagias , Antonio Riotto

On the basis of the quantum Boltzmann equation governing the time-evolution of the density matrix of polarized CMB photons in the primordial scalar perturbations of metric, we calculate the B-mode spectrum of polarized CMB photons…

宇宙学与河外天体物理 · 物理学 2014-11-19 Jafar Khodagholizadeh , Rohoollah Mohammadi , She-Sheng Xue

For the past decade, the BICEP/Keck collaboration has been operating a series of telescopes at the Amundsen-Scott South Pole Station measuring degree-scale $B$-mode polarization imprinted in the Cosmic Microwave Background (CMB) by…

Precise measurements of the cosmic microwave background (CMB) are crucial in cosmology, because any proposed model of the universe must account for the features of this radiation. Of all CMB measurements that the scientific community has…

The absence of large-angle correlations in the temperature of the cosmic microwave background (CMB), confirmed by three independent satellite missions, creates significant tension with the standard model of cosmology. Previous work has…

宇宙学与河外天体物理 · 物理学 2024-04-15 Jingwei Liu , Fulvio Melia

Recently ACTPol has measured the cosmic microwave background (CMB) B-mode and E-mode polarizations and obtained TE, EE, BB, TB and EB power spectra in the multipole range 225-8725. In our previous paper (Ap. J. 792 (2014) 35 [Paper I]), we…

宇宙学与河外天体物理 · 物理学 2016-06-09 Hsien-Hao Mei , Wei-Tou Ni , Wei-Ping Pan , Lixin Xu , Sperello di Serego Alighieri

We investigate the impact of a hypothesized delayed initiation of inflation, characterized by a cutoff k_min to the primordial power spectrum in the cosmic microwave background (CMB). This cutoff affects both the scalar and tensor spectra,…

宇宙学与河外天体物理 · 物理学 2025-07-28 Jingwei Liu , Fulvio Melia

The announcement by BICEP2 of the detection of B-mode polarization consistent with primordial gravitational waves with a tensor-to-scalar ratio, $r=0.2^{+0.07}_{-0.05}$, challenged predictions from most inflationary models of a lower value…

高能天体物理现象 · 物理学 2016-01-20 R. Aloisio , S. Matarrese , A. V. Olinto

CMB polarization provides a unique window into cosmological inflation; the amplitude of the B-mode polarization from last scattering is uniquely sensitive to the energetics of inflation. However, numerous systematic effects arising from…

天体物理学 · 物理学 2009-09-29 Meir Shimon , Brian Keating , Nicolas Ponthieu , Eric Hivon

We compute the bispectrum induced in the cosmic microwave background (CMB) temperature and polarisation by the evolution of the primordial density perturbations using the second-order Boltzmann code SONG. We show that adding polarisation…

宇宙学与河外天体物理 · 物理学 2014-12-03 Guido W. Pettinari , Christian Fidler , Robert Crittenden , Kazuya Koyama , Antony Lewis , David Wands

Primordial magnetic fields (PMFs) create a large squeezed-type non-Gaussianity in tensor perturbation, which generates non-Gaussian temperature fluctuations in the cosmic microwave background (CMB). We for the first time derive an…

宇宙学与河外天体物理 · 物理学 2014-11-13 Maresuke Shiraishi , Toyokazu Sekiguchi