Bouncing Cosmologies in Palatini $f(R)$ Gravity

Abstract

We consider the early time cosmology of f(R) theories in Palatini formalism and study the conditions that guarantee the existence of homogeneous and isotropic models that avoid the Big Bang singularity. We show that for such models the Big Bang singularity can be replaced by a cosmic bounce without violating any energy condition. In fact, the bounce is possible even for pressureless dust. We give a characterization of such models and discuss their dynamics in the region near the bounce. We also find that power-law lagrangians with a finite number of terms may lead to non-singular universes, which contrasts with the infinite-series Palatini f(R) lagrangian that one needs to fully capture the effective dynamics of Loop Quantum Cosmology. We argue that these models could also avoid the formation of singularities during stellar gravitational collapse.

8 pages, 4 figures; added references and a short comment in sec.IV

References in corpus (16)

• Quantum Nature of the Big Bang: Improved dynamics
• Quantum Nature of the Big Bang
• Quantum Nature of the Big Bang: An Analytical and Numerical Investigation
• Loop quantum cosmology of k=1 FRW models
• Limit to General Relativity in f(R) theories of gravity
• The matter power spectrum in f(R) gravity
• Loop quantum cosmology and the k = - 1 RW model
• f(R) gravity theories in Palatini formalism: cosmological dynamics and observational constraints
• Closed FRW model in Loop Quantum Cosmology
• Anti-deSitter universe dynamics in LQC
• Hydrogen atom in Palatini theories of gravity
• The viability of theories with matter coupled to the Ricci scalar
• CMB and Matter Power Spectra of Early f(R) Cosmology in Palatini Formalism
• Re-examination of Polytropic Spheres in Palatini f(R) Gravity
• Microscopic and Macroscopic Behaviors of Palatini Modified Gravity Theories
• Covariant Effective Action for Loop Quantum Cosmology from Order Reduction