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We use the cosmic microwave background temperature anisotropy to place limits on large-scale magnetic fields in an inhomogeneous (perturbed Friedmann) universe. If no assumptions are made about the spacetime geometry, only a weak limit can…

Astrophysics · Physics 2017-08-23 C. A. Clarkson , A. A. Coley , R. Maartens , C. G. Tsagas

A physical metric is constructed as one that gives a coordinate independent result for the time delay in infinite order in the perturbation expansion in the gravitational constant. A compact form for the metric is obtained. One result is…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Yukio Tomozawa

Several statistical anomalies in the CMB temperature anisotropies seem to defy the assumption of a homogeneous and isotropic universe. In particular, a dipole modulation has been detected both in WMAP and Planck data. We adapt the…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-29 R. Fernández-Cobos , P. Vielva , D. Pietrobon , A. Balbi , E. Martínez-González , R. B. Barreiro

The disagreement between low- and high-redshift measurements of the Hubble parameter is emerging as a serious challenge to the standard model of cosmology. We develop a covariant cosmographic analysis of the Hubble parameter in a general…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-13 Roy Maartens , Jessica Santiago , Chris Clarkson , Basheer Kalbouneh , Christian Marinoni

We present a model independent and non-parametric reconstruction with a Machine Learning algorithm of the redshift evolution of the Cosmic Microwave Background (CMB) temperature from a wide redshift range $z\in \left[0,3\right]$ without…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-04 Rubén Arjona

The cosmic microwave background radiation (CMB) is now firmly established as a fundamental and essential probe of the geometry, constituents, and birth of the Universe. The CMB is a potent observable because it can be measured with…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 S. Hanany , M. Niemack , L. Page

We study the ability of future CMB anisotropy experiments and redshift surveys to constrain a thirteen-dimensional parameterization of the adiabatic cold dark matter model. Each alone is unable to determine all parameters to high accuracy.…

Astrophysics · Physics 2009-10-07 Daniel J. Eisenstein , Wayne Hu , Max Tegmark

The cosmological principle posits that the universe is statistically homogeneous and isotropic on large scales, implying all matter shares the same rest frame. This principle suggests that velocity estimates of our motion from various…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 Pedro da Silveira Ferreira , Valerio Marra

We develop some ideas about gauge symmetry in the context of Maxwell's theory of electromagnetism in the Hamiltonian formalism. One great benefit of this formalism is that it pairs momentum and configurational degrees of freedom, so that a…

History and Philosophy of Physics · Physics 2021-10-25 Henrique Gomes , Jeremy Butterfield

The redshift of all cosmological sources drifts by a systematic velocity of order a few m/s over a century due to the deceleration of the Universe. The specific functional dependence of the predicted velocity shift on the source redshift…

Astrophysics · Physics 2011-02-11 Abraham Loeb

We apply CMB lensing techniques to large scale structure and solve for the 3-D cosmic tidal field. We use small scale filamentary structures to solve for the large scale tidal shear and gravitational potential. By comparing this to the…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-28 Ue-Li Pen , Ravi Sheth , J. Harnois-Deraps , Xuelei Chen , Zhigang Li

The thermodynamic and dynamical properties of a variable dark energy model with density scaling as rho_x \propto (1+z)^m, z being the redshift, are discussed following the outline of Jetzer et al. This kind of models are proven to lead to…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-08 Philippe Jetzer , Crescenzo Tortora

It has recently been shown that second-order corrections to the background distance-redshift relation can build up significantly at large redshifts, due to an aggregation of gravitational lensing events. This shifts the expectation value of…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-17 Camille Bonvin , Chris Clarkson , Ruth Durrer , Roy Maartens , Obinna Umeh

In pregeometry a metric arises as a composite object at large distances. We investigate if its signature, which distinguishes between time and space, could be a result of the dynamics rather than being built in already in the formulation of…

General Relativity and Quantum Cosmology · Physics 2022-06-29 C. Wetterich

As cosmology rapidly approaches the data-dominated phase of stage IV large scale structure surveys, the modelling of nonlinear scales has become a serious challenge that faces the community, particularly when analysing models beyond $w$CDM.…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-14 Sankarshana Srinivasan , Shreya Prabhu , Kai Lehman , Ajiv Krishnan V. , Jochen Weller

The quantum metric tensor was introduced for defining the distance in the parameter space of a system. However, it is also useful for other purposes, like predicting quantum phase transitions. Due to the physical information this tensor…

Quantum Physics · Physics 2016-05-27 J. Alvarez-Jimenez , J. D. Vergara

The growth index $\gamma$ is a powerful trigger for detecting deviations from $\Lambda$CDM. However, its value is often determined by considering an asymptotic constant value that works for all redshift, or else following a chosen…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-26 Ziad Sakr , Jinglan Zheng

The observed hemispherical asymmetry in CMB map can be explained by modulation from a long wavelength super horizon mode which non-linearly couples to the CMB modes. We address the criticism in [1] about the role of non-Gaussianities in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Mohammad Hossein Namjoo , Ali Akbar Abolhasani , Shant Baghram , Hassan Firouzjahi

The main purpose of this work is to obtain the metric of a Charge Tempered Cosmological Model, a slightly modified Standard Cosmological Model by a small excess of charge density, distributed uniformly in accordance with the Cosmological…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Mario Goto

Redshift-space clustering anisotropies caused by cosmic peculiar velocities provide a powerful probe to test the gravity theory on large scales. However, to extract unbiased physical constraints, the clustering pattern has to be modelled…

Cosmology and Nongalactic Astrophysics · Physics 2017-03-28 Federico Marulli , Alfonso Veropalumbo , Lauro Moscardini , Andrea Cimatti , Klaus Dolag