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In a recent paper we considered the possibility of a scalar field providing an explanation for the cosmic acceleration. Our model had the interesting properties of attractor-like behavior and having its parameters of O(1) in Planck units.…

天体物理学 · 物理学 2010-04-08 Constantinos Skordis , Andreas Albrecht

The recent measurements of the power spectrum of Cosmic Microwave Background anisotropies are consistent with the simplest inflationary scenario and big bang nucleosynthesis constraints. However, these results rely on the assumption of a…

天体物理学 · 物理学 2009-11-07 Carolina J. Odman , Alessandro Melchiorri , Michael P. Hobson , Anthony N. Lasenby

The spectral variation of the cosmic microwave background (CMB) as observed by WMAP was tested using foreground reduced WMAP5 data, by producing subtraction maps at the 1$^\circ$ angular resolution between the two cosmological bands of V…

宇宙学与河外天体物理 · 物理学 2015-05-13 Bi-Zhu Jiang , Richard Lieu , Shuang-Nan Zhang , Bart Wakker

In this article we propose a novel test for statistical anisotropy of the CMB. The test is based on the fact, that the Galactic foregrounds have a remarcably strong symmetry with respect to their antipodal points and with respect to the…

宇宙学与河外天体物理 · 物理学 2015-05-28 P. Naselsky , M. Hansen , J. Kim

Hot gas in filamentary structures induces CMB aniostropy through the SZ effect. Guided by results from N-body simulations, we model the morphology and gas properties of filamentary gas and determine the power spectrum of the anisotropy. Our…

宇宙学与河外天体物理 · 物理学 2015-06-11 Meir shimon , Sharon Sadeh , Yoel Rephaeli

We investigate cosmological solutions of the chameleon model with a non-minimal coupling between the matter and the scalar field through a conformal factor with gravitational strength. By considering the spatially flat FLRW metric and the…

广义相对论与量子宇宙学 · 物理学 2023-11-01 Raziyeh Zaregonbadi , Nasim Saba , Mehrdad Farhoudi

We show that the difference between the theoretically expected and measured by WMAP amplitude of the quadrupole fluctuations of CMB can be related to the impact of the anisotropic curvature of the homogeneous universe dominated by the dark…

天体物理学 · 物理学 2008-11-26 M. Demiański , A. G. Doroshkevich

Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure. In this paper we develop and test a new statistic based on anisotropies in the…

天体物理学 · 物理学 2009-11-13 Will J Percival , Martin White

Modern cosmology has now emerged as a testing ground for theories beyond the standard model of particle physics. In this paper, we consider quantum fluctuations of the inflaton scalar field on certain noncommutative spacetimes and look for…

天体物理学 · 物理学 2009-03-24 Earnest Akofor , A. P. Balachandran , Sang G. Jo , Anosh Joseph , Babar A. Qureshi

Recently, BICEP2 collaboration has released their results on the measurements of the CMB polarizations. In the framework of the $\Lambda$CDM with a power law form of the scalar primordial power spectrum, this new measurement on the B-mode…

宇宙学与河外天体物理 · 物理学 2014-05-08 Hong Li , Jun-Qing Xia , Xinmin Zhang

We consider structure formation and CMB anisotropies in a closed universe, both with and without a cosmological constant. The CMB angular power spectrum and the matter transfer function are presented, along with a discussion of their…

天体物理学 · 物理学 2009-08-18 Martin White , Douglas Scott

The recent three-year WMAP data have confirmed the anomaly concerning the low quadrupole amplitude compared to the best-fit \Lambda CDM prediction. We show that, allowing the large-scale spatial geometry of our universe to be…

天体物理学 · 物理学 2008-12-18 L. Campanelli , P. Cea , L. Tedesco

If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenarios. One interesting possibility is presented by shear-free…

宇宙学与河外天体物理 · 物理学 2015-07-22 Thiago S. Pereira , Guillermo A. Mena Marugán , Saulo Carneiro

In this Letter, we propose to detect the interaction of a hypothetical coherently evolving cosmological scalar field with an orbital network of quantum sensors, focusing on the GPS satellite network as a test example. Cosmological…

广义相对论与量子宇宙学 · 物理学 2024-08-22 Yu Li , Ruolin Liu , Conner Dailey , Niayesh Afshordi

We question the global universe isotropy by probing the alignment of local structures in the cosmic microwave background (CMB) radiation. The original method proposed relies on a steerable wavelet decomposition of the CMB signal on the…

天体物理学 · 物理学 2007-05-23 Y. Wiaux , P. Vielva , E. Martinez-Gonzalez , P. Vandergheynst

On the galactic scale the universe is inhomogeneous and redshift $z$ is occasionally less than zero. A scalar potential model (SPM) that links the galaxy scale $z$ to the cosmological scale $z$ of the Hubble Law is postulated. Several…

天体物理学 · 物理学 2009-07-01 John C. Hodge

The first-year WMAP data, in combination with any one of a number of other cosmic probes, show that we live in a flat \Lambda-dominated CDM universe with \Omega_m ~ 0.27 and \Omega_\Lambda ~ 0.73. In this model the late-time action of the…

The idea that coherent oscillations of a scalar field, oscillating over a time period that is much shorter than the cosmological timescale, can exhibit cold dark matter (CDM) like behavior was previously established. In our work we first…

广义相对论与量子宇宙学 · 物理学 2025-12-24 Priyanka Saha , Dipanjan Dey , Kaushik Bhattacharya

We consider the FRW cosmological model in which the matter content of universe (playing a role of inflaton or quintessence) is given by a novel generalization of the massive scalar field. The latter is a scalar version of the recently…

广义相对论与量子宇宙学 · 物理学 2017-09-05 Jakub Mielczarek , Tomasz Trześniewski

We study the cosmological evolution of scalar fields with arbitrary potentials in the presence of a barotropic fluid (matter or radiation) without making any assumption on which term dominates. We determine what kind of potentials V(phi)…

高能物理 - 唯象学 · 物理学 2013-05-29 A. de la Macorra , G. Piccinelli