Bouncing Cosmologies in Palatini $fR$ Gravity - General Relativity and Quantum CosmologyReportar como inadecuado




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Abstract: We consider the early time cosmology of fR theories in Palatini formalismand study the conditions that guarantee the existence of homogeneous andisotropic models that avoid the Big Bang singularity. We show that for suchmodels the Big Bang singularity can be replaced by a cosmic bounce withoutviolating any energy condition. In fact, the bounce is possible even forpressureless dust. We give a characterization of such models and discuss theirdynamics in the region near the bounce. We also find that power-law lagrangianswith a finite number of terms may lead to non-singular universes, whichcontrasts with the infinite-series Palatini fR lagrangian that one needs tofully capture the effective dynamics of Loop Quantum Cosmology. We argue thatthese models could also avoid the formation of singularities during stellargravitational collapse.



Autor: Carlos Barragan, Gonzalo J. Olmo, Helios Sanchis-Alepuz

Fuente: https://arxiv.org/







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