The Raychaudhuri equation in homogeneous cosmologies
In this work we address the issue of studying the conditions required to guarantee the Focusing Theorem for both null and time like geodesic congruences by using the Raychaudhuri equation. In particular we study the case of Friedmann-Robertson-Walker as well as more general Bianchi Type I spacetimes...
| Autores: | , , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2014 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/35052 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/35052 |
| Access Level: | acceso abierto |
| Palabra clave: | 53 R-n-gravity Dark energy Relativistic theory Machs principle Cpt violation Supergravity Supersymmetry Supernovae Constant Geometry Física (Física) 22 Física |
| Sumario: | In this work we address the issue of studying the conditions required to guarantee the Focusing Theorem for both null and time like geodesic congruences by using the Raychaudhuri equation. In particular we study the case of Friedmann-Robertson-Walker as well as more general Bianchi Type I spacetimes. The fulfillment of the Focusing Theorem is mandatory in small scales since it accounts for the attractive character of gravity. However, the Focusing Theorem is not satisfied at cosmological scales due to the measured negative deceleration parameter. The study of the conditions needed for congruences convergence is not only relevant at the fundamental level but also to derive the viability conditions to be imposed on extended theories of gravity describing the different expansion regimes of the universe. We illustrate this idea for f (R) gravity theories. |
|---|