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We investigate the global solutions of the Dirac equation on the Anti-de-Sitter Universe. Since this space is not globally hyperbolic, the Cauchy problem is not, {\it a priori}, well-posed. Nevertheless we can prove that there exists…

Mathematical Physics · Physics 2008-11-26 Alain Bachelot

We made an analysis of the equations of motion which are obtained from the one - loop effective action for Brans-Dicke gravity with N dilaton - coupled massless fermions in a time-dependent conformally flat background. Various particular…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Geyer , V. F. Kovalev

The Jordan-Brans-Dicke theory of gravitation, which promotes the gravitational constant to a dynamical scalar field, predicts a value for the Eddington-Robertson post-Newtonian parameter gamma that is significantly different from the…

General Relativity and Quantum Cosmology · Physics 2012-12-12 John W. Moffat , Viktor T. Toth

Dynamical systems methods are used to investigate a cosmological model with non-minimally coupled scalar field and asymptotically quadratic potential function. We found that for values of the non-minimal coupling constant parameter…

General Relativity and Quantum Cosmology · Physics 2021-07-15 Orest Hrycyna

In this work we have studied the possibility of obtaining cosmic acceleration in Brans-Dicke theory with varying or constant $\omega$ (Brans- Dicke parameter) and with or without self-interacting potential, the background fluid being…

General Relativity and Quantum Cosmology · Physics 2009-11-13 Writambhara Chakraborty , Ujjal Debnath

Using scalar-vector-tensor Brans Dicke (VBD) gravity [3] in presence of self interaction BD potential $V(\phi)$ and perfect fluid matter field action we solve corresponding field equations via dynamical system approach for flat Friedmann…

General Physics · Physics 2017-03-08 H. Ghaffarnejad , E. Yaraie

We study the Brans-Dicke model in the presence of an axion. The dynamical equations are solved when the fields are space independent and the metric is spatially flat. It is found that at late time the scale factor undergoes decelerated…

High Energy Physics - Theory · Physics 2009-10-30 Sudipta Mukherji

We propose a unimodular version of the Brans-Dicke theory designed with a constrained Lagrangian formulation. The resulting field equations are traceless. The vacuum solutions in the cosmological background reproduce the corresponding…

General Relativity and Quantum Cosmology · Physics 2022-07-28 Alexandre M. R. Almeida , Júlio C. Fabris , Mahamadou Hamani Daouda , Richard Kerner , Hermano Velten , Wiliam S. Hipólito-Ricaldi

We consider a generalized Brans-Dicke model in which the scalar field has a potential function and is also allowed to couple non-minimally with the matter sector. This anomalous gravitational coupling can in principle avoid the model to…

General Relativity and Quantum Cosmology · Physics 2015-06-18 Yousef Bisabr

The Hamiltonian of any quantum cosmological model must obey some conditions in order to be self-adjoint, or to admit self-adjoint extensions. We will consider in this paper the self-adjoint character of the Hamiltonian resulting from the…

General Relativity and Quantum Cosmology · Physics 2017-09-20 Carla Rodrigues Almeida , Antônio Brasil Batista , Júlio César Fabris , Nelson Pinto-Neto

We study the effects of magnetic fields of non-linear electrodynamics in chameleonic Brans-Dicke theory under the existence of anisotropic spherical fluid. In particular, we explore dissipative and non-dissipative self-gravitating systems…

General Relativity and Quantum Cosmology · Physics 2024-10-03 Z. Yousaf , M. Z. Bhatti , S. Rehman , Kazuharu Bamba

Wyman's less known static and spherically symmetric solution of the Einstein-Klein-Gordon equations and its recent generalization for positive cosmological constant are discussed, showing that they contain central naked singularities. By…

General Relativity and Quantum Cosmology · Physics 2019-09-18 Ali Banijamali , Behnaz Fazlpour , Valerio Faraoni

The late-time cosmological dynamics of disformal gravity are investigated using dynamical systems methods. It is shown that in the general case there are no stable attractors that screen fifth-forces locally and simultaneously describe a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-23 Jeremy Sakstein

Contrary to common belief, the standard tenet of Brans-Dicke theory reducing to general relativity when omega tends to infinity is false if the trace of the matter energy-momentum tensor vanishes. The issue is clarified in a new approach…

General Relativity and Quantum Cosmology · Physics 2011-08-17 Valerio Faraoni

In this paper first we study Brans-Dicke equations with the cosmological constant to find an exact solution in the spatially flat Robertson-Walker metric. Then we use Observational Hubble data, the baryon acoustic oscillation distance ratio…

General Relativity and Quantum Cosmology · Physics 2020-08-26 Hassan Amirhashchi , Anil Kumar Yadav

We derive the global properties of static spherically symmetric solutions to the Einstein-Maxwell-dilaton system in the presence of an arbitrary exponential dilaton potential. We show that -- with the exception of a pure cosmological…

General Relativity and Quantum Cosmology · Physics 2014-11-17 S. J. Poletti , D. L. Wiltshire

We investigate chameleonic Brans--Dicke model applied to the FRW universes. A framework to study stability and attractor solutions in the phase space is developed for the model. We show that depending on the matter field and stability…

General Relativity and Quantum Cosmology · Physics 2011-06-09 Hossein Farajollahi , Amin Salehi

We consider a generalized Brans-Dicke model in which the scalar field has a self-interacting potential function. The scalar field is also allowed to couple non-minimally with the matter part. We assume that it has a chameleon behavior in…

High Energy Physics - Theory · Physics 2019-01-21 Yousef Bisabr

We derive a new parametric class of exact cosmological solutions to Brans-Dicke theory of gravity with a self-interacting scalar field and a barotropic perfect fluid of ordinary matter, by assuming a linear relationship between the Hubble…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Olga Arias , Israel Quiros

We interpret the Brans-Dicke gravity from entropic viewpoint. We first apply the Verlinde's entropic formalism in the Einstein frame, then perform the conformal transformation which connects the Einstein frame to the Jordan frame. The…

High Energy Physics - Theory · Physics 2015-05-28 Ee Chang-Young , Kyoungtae Kimm , Daeho Lee