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Related papers: Dark energy in conformal Killing gravity

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Motivated by results implying that the constituents of dark matter (DM) might be collisional, we consider a cosmological (toy-) model, in which the DM itself possesses some sort of thermodynamic properties. In this case, not only can the…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Kostas Kleidis , Nicholas K. Spyrou

We study physics concerning the cosmological constant problem in the framework of effective field theory and suggest that a dominant part of dark energy can originate from gravitational corrections of vacuum energy, under the assumption…

High Energy Physics - Theory · Physics 2017-02-24 Yugo Abe , Masaatsu Horikoshi , Yoshiharu Kawamura

We consider a generic cosmological model which allows for non-gravitational direct couplings between dark matter and dark energy. The distinguishing cosmological features of these couplings can be probed by current cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-17 Carsten van de Bruck , Jurgen Mifsud

In trying to explain the present accelerated expansion of the universe in the light of a five-dimensional Brans-Dicke theory, it is found that the fifth dimension itself here acts as a source of dark energy. It may be taken as a…

General Physics · Physics 2019-01-30 Koijam Manihar Singh , Kangujam Priyokumar Singh

The introduction of an interaction for dark energy to the standard cosmology offers a potential solution to the cosmic coincidence problem. We examine the conditions on the dark energy density that must be satisfied for this scenario to be…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Micheal S. Berger , Hamed Shojaei

Based on a comprehensive analysis of recent observational data-a combination of DESI DR1, Planck CMB, and Pantheon+ SN Ia-this study critically evaluates the two dark energy (DE) proposals within Harada's Conformal Killing Gravity (CKG)…

General Relativity and Quantum Cosmology · Physics 2025-11-20 Mohsen Khodadi , Gaetano Lambiase , Javad. T. Firouzjaee

The problem of dark energy arises due to its self-gravitating properties. Therefore explaining vacuum energy may become a question for the realm of quantum gravity, that can be addressed within string theory context. In this talk I…

High Energy Physics - Theory · Physics 2007-05-23 L. Mersini , M. Bastero-Gil

Dark energy is one of the mysteries of modern science. It is unlike any known form of matter or energy and has been detected so far only by its gravitational effect of repulsion. Owing to its effects being discernible only at very very…

Cosmology and Nongalactic Astrophysics · Physics 2009-08-25 Aruna Kesavan

A long-standing problem of theoretical physics is the exceptionally small value of the cosmological constant $\Lambda \sim 10^{-120}$ measured in natural Planckian units. Here we derive this tiny number from a toroidal string cosmology…

High Energy Physics - Theory · Physics 2009-11-07 Paul H. Frampton

Recently, the vacuum energy of the QCD ghost in a time-dependent background is proposed as a kind of dark energy candidate to explain the acceleration of the Universe. In this model, the energy density of the dark energy is proportional to…

High Energy Physics - Theory · Physics 2012-10-03 Chao-Jun Feng , Xin-Zhou Li , Xian-Yong Shen

The consideration of dark energy's quanta, required also by thermodynamics, introduces its chemical potential into the cosmological equations. Isolating its main contribution, we obtain solutions with dark energy decaying to matter or…

Astrophysics · Physics 2008-11-26 J. Besprosvany

We obtain the analogues of the Friedman equations in an emergent gravity scenario in the presence of dark energy. The background metric is taken to be Friedman-Lemaitre-Robertson-Walker (FLRW). We show that if $\dot\phi ^{2}$ is the dark…

General Relativity and Quantum Cosmology · Physics 2015-02-24 Debashis Gangopadhyay , Goutam Manna

Observations suggest that nearly seventy per cent of the energy density in the universe is unclustered and exerts negative pressure. Theoretical understanding of this component (`dark energy'), which is driving an accelerated expansion of…

Astrophysics · Physics 2007-05-23 T. Padmanabhan

In this paper, it is shown that the cosmological model that was introduced in a sequence of three earlier papers under the title, A Dust Universe Solution to the Dark Energy Problem can be used to analyse and solve the Cosmological…

General Physics · Physics 2008-07-13 James G. Gilson

This short review examines recent progress in understanding dark matter, dark energy, and galactic halos using theory that departs minimally from standard particle physics and cosmology. Strict conformal symmetry (local Weyl scaling…

General Physics · Physics 2015-06-11 Robert K. Nesbet

The Schr\"odinger-Newton equation is a proposed model to explain the localization of macroscopic particles by suppressing quantum dispersion with the particle's own gravitational attraction. On cosmic scales, however, dark energy also acts…

General Relativity and Quantum Cosmology · Physics 2020-04-01 Kelvin , Kelvin Onggadinata , Matthew J. Lake , Tomasz Paterek

In our recently proposed quantum theory of gravity, the universe is made of `atoms' of space-time-matter (STM). Planck scale foam is composed of STM atoms with Planck length as their associated Compton wave-length. The quantum dispersion…

General Relativity and Quantum Cosmology · Physics 2020-08-03 Tejinder P. Singh

Astrophysical observations are pointing out huge amounts of dark matter and dark energy needed to explain the observed large scale structures and cosmic accelerating expansion. Up to now, no experimental evidence has been found, at…

Astrophysics · Physics 2009-11-11 S. Capozziello , V. F. Cardone , A. Troisi

Although the cosmic concordance cosmology is quite successful in fitting data, fine tuning and coincidence problems apparently weaken it. We review several possibilities to ease its problems, by considering various kinds of dynamical Dark…

Astrophysics · Physics 2008-11-26 S. A. Bonometto , R. Mainini , L. P. L. Colombo

Explanations of the late-time cosmic acceleration within the framework of general relativity are plagued by difficulties. General relativistic models are mostly based on a dark energy field with fine-tuned, unnatural properties. There is a…

Astrophysics · Physics 2010-04-22 Ruth Durrer , Roy Maartens
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