Isotropic and anisotropic bouncing cosmologies in Palatini gravity

Carlos Barragán and Gonzalo J. Olmo
Phys. Rev. D 82, 084015 – Published 11 October 2010

Abstract

We study isotropic and anisotropic (Bianchi I) cosmologies in Palatini f(R) and f(R,RμνRμν) theories of gravity with a perfect fluid and consider the existence of nonsingular bouncing solutions in the early universe. We find that all f(R) models with isotropic bouncing solutions develop shear singularities in the anisotropic case. On the contrary, the simple quadratic model R+aR2/RP+RμνRμν/RP exhibits regular bouncing solutions in both isotropic and anisotropic cases for a wide range of equations of state, including dust (for a<0) and radiation (for arbitrary a). It thus represents a purely gravitational solution to the big bang singularity and anisotropy problems of general relativity without the need for exotic (w>1) sources of matter/energy or extra degrees of freedom.

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  • Received 12 July 2010

DOI:https://doi.org/10.1103/PhysRevD.82.084015

© 2010 The American Physical Society

Authors & Affiliations

Carlos Barragán1 and Gonzalo J. Olmo2,*

  • 1Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Madrid, Spain
  • 2Instituto de Estructura de la Materia, CSIC, Serrano 121, 28006 Madrid, Spain; Departamento de Física Teórica and IFIC, Centro Mixto Universidad de Valencia - CSIC, Facultad de Física, Universidad de Valencia, Burjassot-46100, Valencia, Spain; and Physics Department, University of Wisconsin-Milwaukee, P. O. Box 413, Milwaukee, Wisconsin 53201 USA

  • *gonzalo.olmo@uv.es

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Issue

Vol. 82, Iss. 8 — 15 October 2010

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