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We present an analysis of the phase space of cosmological models based on a non minimal coupling between the geometry and a fermionic condensate. We obtain that the strong constraint coming from the Dirac equations allows a detailed design…

General Relativity and Quantum Cosmology · Physics 2018-04-20 Sante Carloni , Stefano Vignolo , Roberto Cianci

The coupling between the dark components provides a new approach to mitigate the coincidence problem of cosmological standard model. In this paper, dark energy is treated as a fluid with a constant equation of state, whose coupling with…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-18 Weiqiang Yang , Lixin Xu

From a variational action with non-minimal coupling with a scalar field and classical scalar and fermionic interaction, cosmological field equations can be obtained. Imposing a FLRW metric the equations lead directly to a cosmological model…

General Relativity and Quantum Cosmology · Physics 2011-11-29 Samuel Lepe , Javier Lorca , Francisco Peña , Yerko Vásquez

Determination of cosmological parameters is a major goal in cosmology at present. The availability of improved data sets necessitates the development of novel statistical tools to interpret the inference from a cosmological model. In this…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 Ranbir Sharma , H K Jassal

A model for the Universe is proposed whose constituents are: (a) a dark energy field modeled by a fermionic field non-minimally coupled with the gravitational field, (b) a matter field which consists of pressureless baryonic and dark matter…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. O. Ribas , F. P. Devecchi , G. M. Kremer

We study observational signatures of non-gravitational interactions between the dark components of the cosmic fluid, which can be either due to creation of dark particles from the expanding vacuum or an effect of the clustering of a…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-10 Micol Benetti , Welber Miranda , Humberto A. Borges , Cassio Pigozzo , Saulo Carneiro , Jailson S. Alcaniz

We study the spherical collapse model in dark energy cosmologies, in which dark energy is modelled as a minimally coupled scalar field. We first follow the standard assumption that dark energy does not cluster on the scales of interest.…

Astrophysics · Physics 2009-11-10 D. F. Mota , C. van de Bruck

We study the minimally and non-minimally coupled scalar field models as possible alternatives for dark energy, the mysterious energy component that is driving the accelerated expansion of the universe. After discussing the dynamics at both…

General Relativity and Quantum Cosmology · Physics 2019-12-03 Zahra Davari , Valerio Marra , Mohammad Malekjani

Thawing quintessence scalar field models with the various potential forms to explain the late-time cosmic acceleration are compared to the {\Lambda}CDM model in detail by analyzing cosmological parameters with a set of observational data…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 Fereshteh Felegary , Kazuharu Bamba

We show that a Universe with a nonminimally coupled scalar field can fit current measurements of the expansion rate of the Universe better than the standard $\Lambda$-Cold Dark Matter ($\Lambda$CDM) model or other minimally coupled dark…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-10 William J. Wolf , Pedro G. Ferreira , Carlos García-García

We present a fast Markov Chain Monte-Carlo exploration of cosmological parameter space. We perform a joint analysis of results from recent CMB experiments and provide parameter constraints, including sigma_8, from the CMB independent of…

Astrophysics · Physics 2008-11-26 Antony Lewis , Sarah Bridle

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…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-22 Chao-Jun Feng , Xin-Zhou Li , Xian-Yong Shen

We briefly discuss the intriguing case of a phenomenological non-gravitational coupling in the dark sector, where the interaction is parameterized as an energy transfer either from dark matter to dark energy or the opposite. We show that a…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-04 Riccardo Murgia

We consider nonlinear redshift-dependent equation of state parameters as dark energy models in a spatially flat Friedmann-Lema\^itre-Robertson-Walker universe. To depict the expansion history of the universe in such cosmological scenarios,…

General Relativity and Quantum Cosmology · Physics 2018-02-06 Weiqiang Yang , Supriya Pan , Andronikos Paliathanasis

In this study, motivated by recent results from DESI DR2 suggesting the existence of evolving/interacting dark energy, we analyze spatially flat FLRW interacting scalar-tensor cosmological models with non-minimal coupling (NMC) between the…

General Relativity and Quantum Cosmology · Physics 2026-03-12 Marcin Postolak

We do a detailed analysis of a well-theoretically motivated interacting dark energy scalar field model with a time-varying interaction term. Using current cosmological datasets from CMB, BAO, Type Ia Supernova, $H(z)$ measurements from…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-11 Trupti Patil , Ruchika , Sukanta Panda

We reexamine interactions between the dark sectors of cosmology, with a focus on robust constraints that can be obtained using only mildly nonlinear scales. While it is well known that couplings between dark matter and dark energy can be…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-18 V Miranda , Mariana Carrillo González , Elisabeth Krause , Mark Trodden

We study CMB constraints on a model with a cosmological constant and a fraction of dark matter non-minimally coupled to a massless scalar field. In this scenario, there is an extra gravity-like fifth force which can affect the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-09 Sophie C. F. Morris , Anne M. Green

A cosmological model is proposed for the current Universe consisted of non-interacting baryonic matter and interacting dark components. The dark energy and dark matter are coupled through their effective barotropic indexes, which are…

Astrophysics · Physics 2009-06-15 Luis P. Chimento , Monica Forte , Gilberto M. Kremer

The paper deals with a theoretical model for interacting dark energy. The interaction between the cold dark matter (dust) and the dark energy has been assumed to be non-gravitational in nature. Exact analytic cosmological solutions are…

General Relativity and Quantum Cosmology · Physics 2015-07-31 Supriya Pan , Subhra Bhattacharya , Subenoy Chakraborty
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