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Related papers: Modified Gravity and the CMB

200 papers

We investigate the impact of peculiar velocity effects due to the motion of the solar system relative to the microwave background (CMB) on high resolution CMB experiments. It is well known that on the largest angular scales the combined…

Astrophysics · Physics 2009-11-07 Anthony Challinor , Floor van Leeuwen

We propose a method to study and constrain modified gravity theories for dark matter using CMB temperature anisotropies and polarization. We assume that the theories considered here have already passed the matter power-spectrum test of…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Baojiu Li , John D. Barrow , David F. Mota , HongSheng Zhao

We provide a cosmological test of modified gravity with two tensorial degrees of freedom and no extra propagating scalar mode. The theory of gravity we consider admits a cosmological model that is indistinguishable from the $\Lambda$CDM…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-01 Takashi Hiramatsu , Tsutomu Kobayashi

We study the linear and nonlinear structure formation in the dilaton and symmetron models of modified gravity using a generic parameterisation which describes a large class of scenarios using only a few parameters, such as the coupling…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Philippe Brax , Anne-Christine Davis , Baojiu Li , Hans A. Winther , Gong-Bo Zhao

We present constraints on the cosmic growth history with recent cosmological data, allowing for deviations from Lambda CDM as might arise if cosmic acceleration is due to modifications to GR or inhomogeneous dark energy. We combine measures…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-12 Rachel Bean , Matipon Tangmatitham

Inspired by quantum gravitational physics, the approach of non-commutative (NC) phase space leads to a modified dispersion relation of gravitational waves. This feature, if applied to the very early universe, gives rise to a modified power…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-20 Yi-Fu Cai , Yi Wang

In this work we systematically study the linear and nonlinear structure formation in chameleon theories of modified gravity, using a generic parameterisation which describes a large class of models using only 4 parameters. For this we have…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-24 Philippe Brax , Anne-C. Davis , Baojiu Li , Hans A. Winther , Gong-Bo Zhao

We study systematically which features in the cosmic microwave background (CMB) and large-scale structure (LSS) probe various inhomogeneous properties of the dark sectors (including neutrinos, dark matter, and dark energy). We stress, and…

Astrophysics · Physics 2007-07-11 Sergei Bashinsky

In the standard inflationary scenario, primordial perturbations are adiabatic. The amplitudes of most types of isocurvature perturbations are generally constrained by current data to be small. If, however, there is a baryon-density…

Cosmology and Nongalactic Astrophysics · Physics 2016-02-24 Julian B. Muñoz , Daniel Grin , Liang Dai , Marc Kamionkowski , Ely D. Kovetz

We study the cosmic microwave background (CMB) anisotropy in the scenario where the baryon asymmetry of the universe is generated from a condensation of a scalar field. In such a scenario, the scalar condensation may acquire fluctuation…

High Energy Physics - Phenomenology · Physics 2009-09-29 Takeo Moroi , Hitoshi Murayama

We show that modified gravity presents distinctive nonlinear features on the Cosmic Microwave Background (CMB) anisotropies comparing with General Relativity (GR). We calculate the contribution to the CMB non-Gaussianity from nonlinear…

General Relativity and Quantum Cosmology · Physics 2011-08-09 Xian Gao

Non-Planckian (NP) spectral modifications of the CMB radiation spectrum can be produced due to the existence of a non-zero value of the plasma frequency at the recombination epoch. We present here an analysis of NP effects on the radio…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Sergio Colafrancesco , Mohammad Shehzad Emritte , Paolo Marchegiani

We present a detailed analytical study of ultra-relativistic neutrinos in cosmological perturbation theory and of the observable signatures of inhomogeneities in the cosmic neutrino background. We note that a modification of perturbation…

Astrophysics · Physics 2008-11-26 Sergei Bashinsky , Uros Seljak

Testing gravity and the concordance model of cosmology, $\Lambda$CDM, at large scales is a key goal of this decade's largest galaxy surveys. Here we present a comparative study of dark matter power spectrum predictions from different…

The majoron provides an attractive dark matter candidate, directly associated to the mechanism responsible for spontaneous neutrino mass generation within the standard model framework. Here we update the cosmological and astrophysical…

High Energy Astrophysical Phenomena · Physics 2013-09-26 Massimiliano Lattanzi , Signe Riemer-Sorensen , Mariam Tortola , Jose W. F. Valle

We present a case that current observations may already indicate new gravitational physics on cosmological scales. The excess of power seen in the Lyman-alpha forest and small-scale CMB experiments, the anomalously large bulk flows seen…

Astrophysics · Physics 2010-04-23 Niayesh Afshordi , Ghazal Geshnizjani , Justin Khoury

Recent observations of the cosmic microwave background (CMB) have extended the measured power spectrum to higher multipoles $l\gtrsim$1000, and there appears to be possible evidence for excess power on small angular scales. The primordial…

Astrophysics · Physics 2009-02-19 D. Yamazaki , K. Ichiki , T. Kajino , G. J. Mathews

In many versions of brane model, the modulus field of extra dimensions, the radion, could have cosmological evolution, which induces variation of the Higgs vacuum expectation value, $<H>$, resulting in cosmological variation of the electron…

Astrophysics · Physics 2008-11-26 K. C. Chan , M. -C. Chu

Primordial fluctuations in the relative number densities of particles, or isocurvature perturbations, are generally well constrained by cosmic microwave background (CMB) data. A less probed mode is the compensated isocurvature perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-30 Chen He , Daniel Grin , Wayne Hu

The damping of primordial perturbations at small scales gives rise to distortions of the cosmic microwave background (CMB). Here, the dependence of the distortion on the different types of cosmological initial conditions is explored,…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-18 Jens Chluba , Daniel Grin