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Related papers: Hamiltonian General Relativity in CMB frame

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We study the inflation process of universe based on the renormalizable quantum gravity formulated as a conformal field theory (CFT). We show that the power-law CFT spectrum approaches to that of the Harrison-Zel'dovich-Peebles type as the…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-18 Ken-ji Hamada , Shinichi Horata , Tetsuyuki Yukawa

The Cosmological Principle, which states that the Universe is homogeneous and isotropic (when averaged on large scales), is the foundational assumption of Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmologies such as the current standard…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-15 Nathan Secrest , Sebastian von Hausegger , Mohamed Rameez , Roya Mohayaee , Subir Sarkar

A compact overview of the status of CMB anisotropy results and their cosmological interpretation. Section headings: Introduction; CMB Spectrum; Description of CMB Anisotropies; Cosmological Parameters; Physics of Anisotropies; Current…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-09 Douglas Scott , George F. Smoot

The standard $\Lambda$CDM cosmological model informed by cosmic microwave background (CMB) anisotropies makes a precise prediction for the growth of matter density fluctuations over cosmic time on linear scales. A variety of cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-14 Mathew S. Madhavacheril

We expose the scenarios of primordial baryon-photon plasma evolution within the framework of the Milne-like universe models. Recently, such models find a second wind and promise an inflation-free solution of a lot of cosmological puzzles…

General Relativity and Quantum Cosmology · Physics 2019-01-09 S. L. Cherkas , V. L. Kalashnikov

A new method is proposed for modelling spherically symmetric inhomogeneities in the Universe. The inhomogeneities have finite size and are compensated, so they do not exert any measurable gravitational force beyond their boundary. The…

Astrophysics · Physics 2009-10-31 A. N. Lasenby , C. J. L. Doran , M. P. Hobson , Y. Dabrowski , A. D. Challinor

CMB anisotropy data could put powerful constraints on theories of the evolution of our Universe. Using the observations of the large number of CMB experiments, many studies have put constraints on cosmological parameters assuming different…

Astrophysics · Physics 2015-06-24 Marian Douspis

The cosmic microwave background (CMB) provides us with our most direct observational window to the early universe. Observations of the temperature and polarization anisotropies in the CMB have played a critical role in defining the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Anthony Challinor

This paper introduces a systematic treatment of the linear theory of scalar gravitational perturbations in the presence of a fully inhomogeneous magnetic field. The analysis is conducted both in the synchronous and in the conformally…

Astrophysics · Physics 2009-11-10 Massimo Giovannini

The quantization of General Relativity invariant with respect to time-reparametrizations is considered. We construct the Faddeev-Popov generating functional for the unitary perturbation theory in terms of invariants of the kinemetric group…

High Energy Physics - Theory · Physics 2007-05-23 M. Pawlowski , V. N. Pervushin , V. I. Smirichinski

We discuss the time dependence and future of the Cosmic Microwave Background (CMB) in the context of the standard cosmological model, in which we are now entering a state of endless accelerated expansion. The mean temperature will simply…

Astrophysics · Physics 2008-11-26 J. P. Zibin , A. Moss , D. Scott

The measurements of CMB anisotropy have opened up a window for probing the global topology of the universe on length scales comparable to and beyond the Hubble radius. We have developed a new method for calculating the CMB anisotropy in…

Astrophysics · Physics 2007-05-23 Tarun Souradeep , Dmitry Pogosyan , J. Richard Bond

In an ever-expanding spatially closed universe, the fractional change of the volume is the preeminent intrinsic time interval to describe evolution in General Relativity. The expansion of the universe serves as a subsidiary condition which…

General Relativity and Quantum Cosmology · Physics 2018-06-14 Eyo Eyo Ita , Chopin Soo , Hoi-Lai Yu

While many observations support the validity of Einstein's general relativity as the theory of gravity, there are yet many that suggest the presence of new physics. In order to explain the high-redshift supernovae Ia observations together…

Astrophysics · Physics 2008-11-26 R. G. Vishwakarma

The constraints on departures from general relativity (GR) at cosmological length scales due to cosmic microwave background (CMB) data are discussed. The departure from GR is measured by the ratio, parameterized as $1 +\varpi_0 (1 +…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-29 Paolo Serra , Asantha Cooray , Scott F. Daniel , Robert Caldwell , Alessandro Melchiorri

In the covariant cosmological perturbation theory, a 1+3 decomposition ensures that all variables in the frame-independent equations are covariant, gauge-invariant and have clear physical interpretations. We develop this formalism in the…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Fengquan Wu , Li-e Qiang , Xin Wang , Xuelei Chen

We have investigated the constraints on the Cardassian model using the recent results from the Wilkinson Microwave Anisotropy Probe (WMAP) for the locations of the peaks of the Cosmic Microwave Background (CMB) anistropy spectrum. We find…

Astrophysics · Physics 2016-08-30 A. A. Sen , S. Sen

The standard geometrodynamics is transformed into a theory of conformal geometrodynamics by extending the ADM phase space for canonical general relativity to that consisting of York's mean exterior curvature time, conformal three-metric and…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Charles H. -T. Wang

The Cosmic Microwave Background (CMB) power spectrum derived from the first year WMAP data demonstrates an intriguing lack of power at large scales that cannot be accounted for within the framework of the standard cosmological model. We…

Astrophysics · Physics 2009-11-11 Anastasia Niarchou , Andrew H. Jaffe

We study a locally anisotropic model of General Relativity in the framework of a more general geometrical structure than the Riemannian one. In this model the observable anisotropy of the CMBR (WMAP) is represented by a tensor of anisotropy…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Panagiotis G. Labropoulos , Panayiotis C. Stavrinos