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We study the predictions for structure formation in an induced gravity dark energy model with a quartic potential. By developing a dedicated Einstein-Boltzmann code, we study self-consistently the dynamics of homogeneous cosmology and of…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-14 Caterina Umiltà , Mario Ballardini , Fabio Finelli , Daniela Paoletti

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

There has been recent interest in the cosmological consequences of energy-momentum-powered gravity models, in which the matter side of Einstein's equations is modified by the addition of a term proportional to some power, $n$, of the…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-29 M. C. F. Faria , C. J. A. P. Martins , F. Chiti , B. S. A. Silva

We explore the cosmological consequences of kinetically mixed dark photons with a mass between 1 MeV and 10 GeV, and an effective electromagnetic fine structure constant as small as $10^{-38}$. We calculate the freeze-in abundance of these…

High Energy Physics - Phenomenology · Physics 2014-09-05 Anthony Fradette , Maxim Pospelov , Josef Pradler , Adam Ritz

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…

Astrophysics · Physics 2009-08-18 Martin White , Douglas Scott

The massive gravity cosmology is studied in the scenario of big bang nucleosynthesis. By making use of current bounds on the deviation from the fractional mass, we derive the constraints on the free parameters of the theory. The…

General Relativity and Quantum Cosmology · Physics 2015-06-11 G. Lambiase

Cosmology and astrophysics provide various ways to study the properties of dark matter even if they have negligible non-gravitational interactions with the Standard Model particles and remain hidden. We study a type of hidden dark matter…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-03 Weikang Lin , Xingang Chen , Himanish Ganjoo , Liqiang Hou , Katherine J. Mack

We analyze the basic cosmological effects of a population of timelike boundaries -- a form of nontrivial spacetime topology -- containing a boundary layer of quantum stress energy. This accumulation of vacuum fluctuations of quantum fields…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-26 Oliver H. E. Philcox , Eva Silverstein , Gonzalo Torroba

We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place…

High Energy Physics - Phenomenology · Physics 2009-11-10 E. J. Copeland , N. J. Nunes , M. Pospelov

We use large-scale cosmological observations to place constraints on the dark-matter pressure, sound speed and viscosity, and infer a limit on the mass of warm-dark-matter particles. Measurements of the cosmic microwave background (CMB)…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-08 Martin Kunz , Savvas Nesseris , Ignacy Sawicki

Any unified dark matter cosmology can be decomposed into dark matter interacting with vacuum energy, without introducing any additional degrees of freedom. We present observational constraints on an interacting vacuum plus dark energy…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-16 Yuting Wang , David Wands , Lixin Xu , Josue De-Santiago , Alireza Hojjati

We investigate the cosmological behavior in a universe governed by time asymmetric extensions of general relativity, which is a novel modified gravity based on the addition of new, time-asymmetric, terms on the Hamiltonian framework, in a…

General Relativity and Quantum Cosmology · Physics 2015-11-11 Genly Leon , Emmanuel N. Saridakis

The presence of light thermally coupled dark matter affects early expansion history and production of light elements during the Big Bang Nucleosynthesis. Specifically, dark matter that annihilates into Standard Model particles can modify…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-07 Rui An , Vera Gluscevic , Erminia Calabrese , J. Colin Hill

The Standard Cosmological Model has experienced tremendous success at reproducing observational data by assuming a universe dominated by a cosmological constant and dark matter in a flat geometry. However, several studies, based on local…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-29 Jailson S. Alcaniz , Jacinto P. Neto , Farinaldo S. Queiroz , Deivid R. da Silva , Raimindo Silva

Massive neutrinos have a detectable effect on cosmological structure formation, in particular on the large-scale distribution of galaxies. Adding Hot Dark Matter to the now-standard Lambda CDM model leads to a worse fit to large-scale…

Astrophysics · Physics 2007-05-23 Eric Gawiser

For general number of spatial dimensions we investigate the cosmological dynamics driven by a cosmological constant and by a source with barotropic equation of state. It is assumed that for both those sources the energy density can be…

General Relativity and Quantum Cosmology · Physics 2022-11-09 A. A. Saharian , R. M. Avagyan , E. R. Bezerra de Mello , V. Kh. Kotanjyan , T. A. Petrosyan , H. G. Babujyan

VAMP (variable-mass particles) scenarios, in which the mass of the cold dark matter particles is a function of the scalar field responsible for the present acceleration of the Universe, have been proposed as a solution to the cosmic…

Astrophysics · Physics 2009-11-10 Urbano Franca , Rogerio Rosenfeld

We study the pure and thermal states of quantized scalar and tensor perturbations in various epochs of Universe evolution. We calculate the density matrix of non-relativistic particles in an environment of these perturbations. We show that…

General Relativity and Quantum Cosmology · Physics 2021-04-23 Z. Haba

In this paper a new theory of Dark Matter is proposed. Experimental analysis of several Galaxies show how the non-gravitational contribution to galactic Velocity Rotation Curves can be interpreted as that due to the Cosmological Constant…

Astrophysics · Physics 2007-05-23 G. V. Kraniotis , S. B. Whitehouse

We find statistically significant correlations in the cosmological matter power spectrum over the full range of observable scales. While the correlations between individual modes are weak, the band-averaged power spectrum shows strong…

Astrophysics · Physics 2009-10-31 A. Meiksin , Martin White