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We demonstrate that a transition from decelerated to accelerated cosmic expansion arises as a pure interaction phenomenon if pressureless dark matter is coupled to holographic dark energy whose infrared cutoff scale is set by the Hubble…

Astrophysics · Physics 2009-11-11 Winfried Zimdahl , Diego Pavon

By considering the logarithmic correction to the energy density, we study the behavior of Hubble parameter in the holographic dark energy model. We assume that the universe is dominated by interacting dark energy and matter and the…

General Physics · Physics 2011-05-09 H. Mohseni Sadjadi , Mubasher Jamil

Cosmological observations of the recent universe suggest that dark energy equation of state parameter $w$ is growing with time, departing from a cosmological constant for which $w=-1$. Standard quintessence models allow for a varying…

High Energy Physics - Theory · Physics 2025-07-11 David Andriot

A new bound dark energy, BDE, cosmology has been proposed where the dark energy is the binding energy between light meson fields that condense a few tens of years after the big bang. It is reported that the correct dark energy density…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-06 Rodger I. Thompson

Cosmological backreaction has been suggested as an explanation of dark energy and is heavily disputed since. We combine cosmological perturbation theory with Buchert's non-perturbative framework, calculate the relevant averaged observables…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Nan Li , Dominik J. Schwarz

Dark energy, the enigmatic force driving the accelerated cosmic expansion of the universe, is conventionally described as a cosmological constant in the standard $\Lambda$CDM model. However, measurements from the Dark Energy Spectroscopic…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-26 Axel de la Macorra , Jose Agustin Lozano Torres

We examine the evolution of a closed, homogeneous and anisotropic cosmology subject to a variation of the fine structure 'constant', \alpha, within the context of the theory introduced by Bekenstein, Sandvik, Barrow and Magueijo, which…

General Relativity and Quantum Cosmology · Physics 2015-06-15 John D. Barrow , David Sloan

We study the spontaneous baryogenesis scenario in the early universe for three different frameworks of varying constants theories. We replace the constants by dynamical scalar fields playing the role of thermions. We first obtain the…

High Energy Physics - Theory · Physics 2019-03-27 Katarzyna Leszczynska , Mariusz P. Dabrowski , Tomasz Denkiewicz

In this work we consider quantum electromagnetic fields in an expanding universe. We start by reviewing the difficulties found when trying to impose the Lorenz condition in a time-dependent geometry. Motivated by this fact, we explore the…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Jose Beltran Jimenez , Antonio L. Maroto

We extend the dynamical systems analysis of Scalar-Fluid interacting dark energy models performed in C. G. Boehmer et al, Phys. Rev. D 91, 123002 (2015), by considering scalar field potentials beyond the exponential type. The properties and…

General Relativity and Quantum Cosmology · Physics 2017-02-01 Jibitesh Dutta , Wompherdeiki Khyllep , Nicola Tamanini

In the current study, we have reconstructed variable modified Chaplygin gas in the Barrow holographic dark energy framework motivated by many recent studies. We have validated the generalized second law of thermodynamics for the…

General Relativity and Quantum Cosmology · Physics 2025-12-02 Sanjeeda Sultana , Chayan Ranjit , Surajit Chattopadhyay

In order to apply holography and entropy relations to the whole universe, which is a gravitational and thus nonextensive system, for consistency one should use the generalized definition for the universe horizon entropy, namely Tsallis…

General Relativity and Quantum Cosmology · Physics 2018-12-12 Emmanuel N. Saridakis , Kazuharu Bamba , R. Myrzakulov , Fotios K. Anagnostopoulos

Bearing holographic dark energy hypothesis in mind, the ability of vacuum energy in describing the current accelerated universe is studied in the framework of Rastall theory. Here, in addition to the ordinary approach in which it is…

General Relativity and Quantum Cosmology · Physics 2020-11-17 S. Ghaffari , A. A. Mamon , H. Moradpour , A. H. Ziaie

We propose a method to relate the holographic minimal information density to the de Broglie's wavelength at a given universe temperature $T$. To figure this out, we assume that the thermal length of massive and massless constituents…

General Relativity and Quantum Cosmology · Physics 2017-07-11 Orlando Luongo

The purpose of this short review is to describe cosmological models with a linear inhomogeneous time-dependent equation of state (EoS) for the dark energy, when the dark fluid is coupled with dark matter. This may lead to a bounce…

General Relativity and Quantum Cosmology · Physics 2015-03-17 Iver Brevik , Alexander Timoshkin

We investigate cosmological scenarios containing one canonical scalar field with an exponential potential in the context of bouncing models, where the bounce happens due to quantum cosmological effects. The only possible bouncing solutions…

General Relativity and Quantum Cosmology · Physics 2018-05-01 Anna Paula Bacalhau , Nelson Pinto-Neto , Sandro Dias Pinto Vitenti

Following Barrow's idea of fractal black hole horizon, we re-derive black hole entropy of static spherically symmetric black holes. When a black hole absorbs matter its horizon area will increase. Given the spherically fractal structure, we…

General Relativity and Quantum Cosmology · Physics 2022-05-27 Li-Hua Wang , Meng-Sen Ma

In this Letter it is shown that when the holographic dark energy is combined with the Brans-Dicke field equations the transition from decelerated to accelerated expansion of the Universe can be more easily accounted for than when resort to…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Narayan Banerjee , Diego Pavon

One of the main goals of modern cosmology remains to summon up a self consistent policy, able to explain, in the framework of the Einstein's theory, the cosmic speed up and the presence of Dark Matter in the Universe. Accordingly to the…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Alejandro Aviles , Luca Bonanno , Orlando Luongo , Hernando Quevedo

Recent observations from the Dark Energy Spectroscopic Instrument (DESI 2025) indicate a weakening of cosmic acceleration at low redshifts $z < 1$, with effective dark energy equation of state parameters $w_0 > -1$ and $w_a < 0$. We…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-28 John W. Moffat