Título:
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On the non-attractive character of gravity in f(R) theories
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Autores:
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Albareti, F. D. ;
Ruiz Cembranos, José Alberto ;
Cruz Dombriz, Álvaro de la ;
Dobado González, Antonio
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Tipo de documento:
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texto impreso
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Editorial:
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IOP publishing ltd, 2013-07
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Dimensiones:
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application/pdf
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Nota general:
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info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Física
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Tipo = Artículo
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Resumen:
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Raychaudhuri equation is found provided that particular energy conditions are assumed and regardless the considered solution of the Einstein's equations. This fact is usually interpreted as a manifestation of the attractive character of gravity. Nevertheless, a positive contribution to Raychaudhuri equation from space-time geometry should occur since this is the case in an accelerated expanding Robertson-Walker model for congruences followed by fundamental observers. Modified gravity theories provide the possibility of a positive contribution although the standard energy conditions are assumed. We address this important issue in the context of f(R) theories, deriving explicit upper bounds for the contribution of space-time geometry to the Raychaudhuri equation. Then, we examine the parameter constraints for some paradigmatic f(R) models in order to ensure a positive contribution to this equation. Furthermore, we consider the implications of these upper bounds in the equivalent formulation of f(R) theories as a Brans-Dicke model.
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En línea:
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https://eprints.ucm.es/id/eprint/22935/1/DobadoAntonio106.pdf
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