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Related papers: EvoEMD: cosmic evolution with an early matter-domi…

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We discuss the heat history of the early Universe and its further evolution in the framework of modern cosmological models of general relativity (GR) and alternative theories of gravity. Of great importance are the new puzzling forms of…

General Relativity and Quantum Cosmology · Physics 2023-12-21 K. A. Bronnikov , M. I. Kalinin , V. V. Khruschov

The existence of dark matter and dark energy in cosmology is implied by various observations, however, they are still unclear because they have not been directly detected. In this Letter, an unified model of dark energy and dark matter that…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-27 Jiro Matsumoto

The cosmic expansion history proceeds in broad terms from a radiation dominated epoch to matter domination to an accelerated, dark energy dominated epoch. We investigate whether intermittent periods of acceleration are possible in the early…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-21 Eric V. Linder , Tristan L. Smith

The time evolution of cosmological parameters in early Universe at the deconfinement transition is studied by an equation of state (EoS) which takes into account the finite baryon density and the background magnetic field. The non…

High Energy Physics - Phenomenology · Physics 2015-09-30 Paolo Castorina , Vincenzo Greco , Salvatore Plumari

Primordial chemistry began, at the recombination epoch, when the adiabatic expansion caused the temperature of the radiation to fall below 4000K. The chemistry of the early Universe involves the elements hydrogen, its isotope deuterium,…

Astrophysics · Physics 2009-10-31 Denis Puy

We show that in a class of universal extra dimension (UED) models that solves both the neutrino mass and proton decay problems using low scale left-right symmetry, the dark matter of the Universe consists of an admixture of KK photon and KK…

High Energy Physics - Phenomenology · Physics 2009-11-11 Ken Hsieh , R. N. Mohapatra , Salah Nasri

We investigate the cosmological implications of a generalized total equation of state (EoS) model by constraining its parameters using observational datasets to effectively characterize the universe's expansion history and its dynamic…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 M. Koussour , S. Bekov , A. Syzdykova , S. Muminov , I. Ibragimov , J. Rayimbaev

In this review we outline the major points of ab-initio cosmological models focusing on some galaxy evolution unresolved problems. In particular our knowledge of the star formation rate which leads galaxy evolution, i.e. luminosity, colors…

Astrophysics · Physics 2009-09-29 Paola Mazzei

Cosmic acceleration is widely believed to require either a source of negative pressure (i.e., dark energy), or a modification of gravity, which necessarily implies new degrees of freedom beyond those of Einstein gravity. In this paper we…

High Energy Physics - Theory · Physics 2017-06-28 Lasha Berezhiani , Justin Khoury , Junpu Wang

Current cosmological data exhibit a tension between inferences of the Hubble constant, $H_0$, derived from early and late-universe measurements. One proposed solution is to introduce a new component in the early universe, which initially…

Cosmology and Nongalactic Astrophysics · Physics 2020-08-12 J. Colin Hill , Evan McDonough , Michael W. Toomey , Stephon Alexander

One of the main challenges in cosmology is to quantify how small density fluctuations at the recombination epoch z around 1000 evolved into the galaxies and the large-scale structure we observe in the universe today. This thesis discusses…

Astrophysics · Physics 2008-02-03 Max Tegmark

In order to unravel the nature of the dark matter (DM) we have proposed a particle-physics motivated model called Bound Dark Matter (BDM) that consist in DM massless particles above a threshold energy Ec that acquire mass below it due to…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-02 Jorge Mastache , Axel de la Macorra , Jorge L. Cervantes-Cota

The behavior of perturbation in scalar field dark energy and its consequent effect on the cold dark matter (CDM) power spectrum is well understood to be governed by the equation of state (EOS) parameter and the effective speed of sound…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-26 Rizwan Ul Haq Ansari , Sanil Unnikrishnan

Early dark energy (EDE) that behaves like a cosmological constant at early times (redshifts $z\gtrsim3000$) and then dilutes away like radiation or faster at later times can solve the Hubble tension. In these models, the sound horizon at…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-12 Vivian Poulin , Tristan L. Smith , Tanvi Karwal , Marc Kamionkowski

The Dark Ages and the Cosmic Dawn are an untapped well of information about the particle physics properties of dark matter, which may become accessible with future radio telescopes able to probe the 21-cm signal from atomic hydrogen. In…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-22 Markus R. Mosbech , Cristina Benso , Felix Kahlhoefer

The thermodynamic behavior of a decaying vacuum cosmology describing the entire cosmological history evolving between two extreme (early and late time) de Sitter eras is investigated. The thermal evolution from the early de Sitter to the…

General Relativity and Quantum Cosmology · Physics 2015-06-23 J. A. S. Lima , S. Basilakos , Joan Solà

Most of our knowledge of the universe has been obtained from the anisotropy spectrum of the cosmic microwave background and observations of large-scale structures. During the history of the Universe, neutrinos from the early Universe evolve…

General Relativity and Quantum Cosmology · Physics 2023-10-31 Muhammad Yarahmadi , Amin Salehi

Employing the spherical collapse (SC) formalism, we investigate the linear evolution of the matter over-density for energy-momentum-squared gravity (EMSG), which in practical phenomenological terms, one may imagine as an extension of the…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-26 Bita Farsi , Ahmad Sheykhi , Mohsen Khodadi

The primordial nucleosinthesys of the element can be influenced by the transitions of phase that take place after the Big Bang, such as the QCD transition. In order to study the effect of this phase transition, in this work we compute the…

High Energy Physics - Phenomenology · Physics 2015-06-18 G. L. Guardo , V. Greco , M. Ruggieri

We present a modified cosmological scenario that arises from the application of non-extensive thermodynamics with varying exponent. We extract the modified Friedmann equations, which contain new terms quantified by the non-extensive…

General Relativity and Quantum Cosmology · Physics 2019-03-27 Shin'ichi Nojiri , Sergei D. Odintsov , Emmanuel N. Saridakis