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Probing primordial curvature perturbations on small scales, beyond those accessible using cosmic microwave background (CMB) primary anisotropies and Lyman-$\alpha$ forest data, remains a major open challenge. Current constraints on the…

High Energy Physics - Phenomenology · Physics 2025-09-03 Aurora Ireland , Kuver Sinha , Tao Xu

With the release of the data from the Boomerang and MAXIMA-1 balloon flights, estimates of cosmological parameters based on the Cosmic Microwave Background (CMB) have reached unprecedented precision. In this paper I show that it is possible…

Astrophysics · Physics 2009-10-31 William H. Kinney

Standard CMB analysis assumes a direct deterministic mapping between the multipole probed by the CMB $\ell$ and the primordial wavenumber $k$. Since the recombination era has a finite duration, this mapping is probabilistic by construction.…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-20 V. K. Oikonomou

We discuss the polarization signature of primordial gravitational waves imprinted in cosmic microwave background (CMB) anisotropies. The high-energy physics motivated by superstring theory or M-theory generically yield parity violating…

Astrophysics · Physics 2009-06-23 Shun Saito , Kiyotomo Ichiki , Atsushi Taruya

Some theoretical models for the early Universe predict a spike-type enhancement in the primordial power spectrum on a small scale, which would result in forming early-formed dark matter halos~(EFHs). Some recent studies have claimed to have…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-21 Katsuya T. Abe , Hiroyuki Tashiro

We examine the degree to which observations of large-scale cosmic microwave background (CMB) polarization can shed light on the puzzling large-scale power modulation in maps of CMB anisotropy. We consider a phenomenological model in which…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-23 Emory F. Bunn , Qingyang Xue , Haoxuan Zheng

The cosmological magnetic field is one of the important physical quantities which affect strongly the cosmic microwave background (CMB) power spectrum. Recent CMB observations have been extended to higher multipoles $l\gtrsim$1000, and they…

Astrophysics · Physics 2009-11-10 D. G. Yamazaki , K. Ichiki , T. Kajino

Cosmic microwave background (CMB) temperature anisotropies have and will continue to revolutionize our understanding of cosmology. The recent discovery of the previously predicted acoustic peaks in the power spectrum has established a…

Astrophysics · Physics 2011-07-19 Wayne Hu , Scott Dodelson

Large-scale magnetic fields affect the scalar modes of the geometry whose ultimate effect is to determine the anisotropies of the Cosmic Microwave Background (CMB in what follows). For the first time, a consistent numerical approach to the…

Astrophysics · Physics 2010-04-29 Massimo Giovannini , Kerstin E. Kunze

The simplest inflationary models predict a primordial power spectrum (PPS) of the curvature fluctuations that can be described by a power-law function that is nearly scale-invariant. It has been shown, however, that the low-multipole…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-25 Eleonora Di Valentino , Stefano Gariazzo , Martina Gerbino , Elena Giusarma , Olga Mena

Fluctuations in the intensity and polarization of the cosmic microwave background (CMB) and the large-scale distribution of matter in the universe each contain clues about the nature of the earliest moments of time. The next generation of…

We determine the full C_l spectra and correlation functions of the temperature and polarization anisotropies in the CMB, generated by a source modeled by the large N limit of spontaneously broken global O(N)-theories. We point out a problem…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Elisa Fenu , Daniel G. Figueroa , Ruth Durrer , Juan Garcia-Bellido , Martin Kunz

If the universe had a large curvature before inflation there is a deviation from the scale invariant perturbations of the inflaton at the beginning of inflation. This may have some effect on the CMB anisotropy at large angular scales. We…

Astrophysics · Physics 2008-11-26 Eduard Masso , Subhendra Mohanty , Akhilesh Nautiyal , Gabriel Zsembinszki

The temperature and polarization anisotropies of the Cosmic Microwave Background are analyzed under the hypothesis that the same inflationary seed accounting for protogalactic magnetism also affects the Einstein-Boltzmann hierarchy whose…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-02 Massimo Giovannini

Searching for the signal of primordial gravitational waves in the B-modes (BB) power spectrum is one of the key scientific aims of the cosmic microwave background (CMB) polarization experiments. However, this could be easily contaminated by…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Si-Yu Li , Jun-Qing Xia , Mingzhe Li , Hong Li , Xinmin Zhang

We consider the hypothesis that nonlocal, omnidirectional, causally-coherent quantum entanglement of inflationary horizons may account for some well-known measured anomalies of Cosmic Microwave Background (CMB) anisotropy on large angular…

General Relativity and Quantum Cosmology · Physics 2022-02-16 Craig Hogan , Stephan S. Meyer

We study the observational implications of a class of inflationary models wherein the inflaton is coupled to the Einstein tensor through a generalized non-minimal derivative coupling (GNMDC). In particular, we explore whether these models…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-03 Yashi Tiwari , Nilanjandev Bhaumik , Rajeev Kumar Jain

The possibility to have an infinite open inflationary universe inside a bubble of a finite size is one of the most interesting realizations extensively discussed in the literature. The original idea was based on the theory of tunneling and…

Astrophysics · Physics 2009-09-29 Andrei Linde , Misao Sasaki , Takahiro Tanaka

In conventional model independent approaches, the power spectrum of primordial perturbations is characterized by such free parameters as spectral index, its running, the running of running, and the tensor-to-scalar ratio. In this work we,…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-15 Moslem Zarei

Cosmological models predict transfer functions by which primordial density perturbations develop into CMB anisotropy and Large-Scale Structure. We use the current set of observations to reconstruct the primordial power spectrum for standard…

Astrophysics · Physics 2007-05-23 Eric Gawiser
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