Palatini approach to 1/R gravity and its implications to the late Universe

Abstract

By applying the Palatini approach to the 1/R-gravity model it is possible to explain the present accelerated expansion of the Universe. Investigation of the late Universe limiting case shows that: (i) due to the curvature effects the energy-momentum tensor of the matter field is not covariantly conserved; (ii) however, it is possible to reinterpret the curvature corrections as sources of the gravitational field, by defining a modified energy-momentum tensor; (iii) with the adoption of this modified energy-momentum tensor the Einstein's field equations are recovered with two main modifications: the first one is the weakening of the gravitational effects of matter whereas the second is the emergence of an effective varying "cosmological constant"; (iv) there is a transition in the evolution of the cosmic scale factor from a power-law scaling $a\propto t^{11/18}$ to an asymptotically exponential scaling $a\propto \exp (t)$; (v) the energy density of the matter field scales as ${\rho }_m\propto (1/a{)}^{36/11}$; (vi) the present age of the Universe and the decelerated-accelerated transition redshift are smaller than the corresponding ones in the $\Lambda$CDM model.

arXiv comment5 pages and 2 figures. Accepted in PRD

References in corpus (16)

• Measurements of Omega and Lambda from 42 High-Redshift Supernovae
• The Cosmological Constant and Dark Energy
• Cosmological Imprint of an Energy Component with General Equation of State
• Quintessence, Cosmic Coincidence, and the Cosmological Constant
• An alternative to quintessence
• Generalized Chaplygin Gas, Accelerated Expansion and Dark Energy-Matter Unification
• Where new gravitational physics comes from: M-theory?
• 1/R Curvature Corrections as the Source of the Cosmological Acceleration
• Palatini form of 1/R gravity
• Density perturbations in an Universe dominated by the Chaplygin gas
• Cosmological consequences of a Chaplygin gas dark energy
• The Universality of Einstein Equations
• Do SNe Ia Provide Direct Evidence for Past Deceleration of the Universe?
• Cosmological Evolution in 1/R-Gravity Theory
• Viscous cosmological models and accelerated Universes
• Irreversible Processes in a Universe modelled as a mixture of a Chaplygin gas and radiation

Cited by in corpus (39)

• Dynamics of dark energy
• Extended Theories of Gravity and their Cosmological and Astrophysical Applications
• Palatini Approach to Modified Gravity: f(R) Theories and Beyond
• Reconciling dark energy models with f(R) theories
• Observational constraints on dark energy with generalized equations of state
• Covariant conservation of energy momentum in modified gravities
• Accelerated Cosmological Models in Ricci squared Gravity
• Cosmological perturbations in the Palatini formulation of modified gravity
• Spherical symmetry in $f(R)$-gravity
• f(R) gravity theories in Palatini formalism: cosmological dynamics and observational constraints
• PPN-limit of Fourth Order Gravity inspired by Scalar-Tensor Gravity
• Density perturbations in f(R) gravity theories in metric and Palatini formalisms
• Palatini formulation of modified gravity with a nonminimal curvature-matter coupling
• Phantom cosmology with general potentials
• Interacting dark energy in $f(R)$ gravity
• Dark energy exponential potential models as curvature quintessence
• Beyond the perfect fluid hypothesis for dark energy equation of state
• f(R) Gravity: From the Pioneer Anomaly to the Cosmic Acceleration
• Noncommutative geometry inspired black holes in Rastall gravity
• Constraining dark energy models using the lookback time to galaxy clusters and the age of the universe
• Gravitational lensing in fourth order gravity
• Solar System planetary orbital motions and f(R) Theories of Gravity
• Constraining Van der Waals quintessence by observations
• Noether Charge and Black Hole Entropy in Modified Theories of Gravity
• Acceleration of the universe in the Einstein frame of a metric-affine f(R) gravity
• Cosmological perturbations in Palatini modified gravity
• Horizon Entropy in Modified Gravity
• Palatini formulation of the conformally invariant $f\left(R,L_m\right)$ gravity theory
• Inflationary cosmology with Chaplygin gas in Palatini formalism
• The present universe in the Einstein frame, metric-affine R+1/R gravity
• A Note on Energy-Momentum Conservation in Palatini Formulation of L(R) Gravity
• Do sewn singularities falsify the Palatini cosmology?
• A fluid os strings as a viable candidate to the dark side of the universe
• Inflessence: a phenomenological model for inflationary quintessence
• Classical limit of quantum gravity in an accelerating universe
• Weak gravitational lensing by compact objects in fourth order gravity
• 1/R multidimensional gravity with form-fields: stabilization of extra dimensions, cosmic acceleration and domain walls
• Palatini Formalism of 5-Dimensional Kaluza-Klein Theory
• Extended Theories of Gravity in cosmological and astrophysical applications