323,264 research outputs found
The Cauchy problem for metric-affine f(R) gravity in presence of perfect-fluid matter
No full textThe Cauchy problem for metric-affine f(R)-gravity in the manner of Palatini and with torsion, in the presence of perfect fluid matter acting as a source, is discussed following the well-known Bruhat prescriptions for general relativity. The problem results in being well formulated and well posed when the perfect-fluid form of the stress-energy tensor is preserved under conformal transformations and the set of viable f(R)-models is not empty. The key role of conservation laws in the Jordan and in the Einstein frame is also discussed. © 2009 IOP Publishing Ltd
Descripción fluidodinámica de las disipación-difusión en sistemas fermiónicos finitos
No full textFil: Vignolo, Carlos Esteban. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
A comment on 'The Cauchy problem of f(R) gravity'
No full textA critical comment on [N. Lanahan--Tremblay and V. Faraoni, 2007, Class. Quantum Grav., 24, 5667] is given discussing the well-formulation of the Chauchy problem for f(R)-gravity in metric-affine theories
The Cauchy problem for metric-affine f(R)-gravity in presence of perfect-fluid matter
No full textThe Cauchy problem for metric-affine f(R)-gravity à la
Palatini and with torsion, in presence of perfect fluid matter
acting as source, is discussed following the well-known Bruhat
prescriptions for General Relativity. The problem results
well-formulated and well-posed when the perfect-fluid form
of the stress-energy tensor is preserved under conformal
transformations and the set of viable f(R) models is not
empty. The key role of conservation laws in Jordan and in
Einstein frame is also discussed
The Cauchy problem for f(R)-gravity: an overview
No full textWe review the Cauchy problem for f(R) theories of gravity, in metric and metric-affine for- mulations, pointing out analogies and differences with respect to General Relativity. The role of conformal transformations, effective scalar fields and sources in the field equations is discussed in view of the well-posedness of the problem. Finally, criteria of viability of the f(R)-models are considered according to the various matter fields acting as sources
- …
