Modified gravity with an exponential function of curvature

Abstract

The role of an exponential function of the scalar curvature in the modified gravity is analyzed. Two models are proposed. A toy model that complies with local and cosmological constraints and gives appropriate qualitative description of the cosmic evolution. This model contains a saddle matter-dominant critical point that can evolve towards a late time de Sitter attractor. Initial conditions have been proposed, showing that this toy model has an acceptable matter era and gives an approximate qualitative behavior of cosmic evolution. A second viable model, behaves very close to $\Lambda$CDM at early times and can satisfy local and cosmological constraints. It behaves as $R-2\Lambda$ at $R\to \infty$ and tends to zero at $R\to 0$, containing flat spacetime solution. The model gives viable cosmological trajectories that, as the first model, connect the matter dominated point with a late time de Sitter attractor. The cosmic evolution of the main density parameters in this model is consistent with current observations with an equation of state very close to $-1$.

30 pages, 8 figures, version accepted in EPJC

References in corpus (36)

• Dynamics of dark energy
• Unified cosmic history in modified gravity: from F(R) theory to Lorentz non-invariant models
• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• Models of f(R) Cosmic Acceleration that Evade Solar-System Tests
• Disappearing cosmological constant in f(R) gravity
• Modified f(R) gravity consistent with realistic cosmology: from matter dominated epoch to dark energy universe
• Class of viable modified $f(R)$ gravities describing inflation and the onset of accelerated expansion
• Dark energy in modified Gauss-Bonnet gravity: late-time acceleration and the hierarchy problem
• Cosmological viability of f(R)-gravity as an ideal fluid and its compatibility with a matter dominated phase
• Conditions for the cosmological viability of f(R) dark energy models
• Are f(R) dark energy models cosmologically viable ?
• Modified f(R) gravity unifying R^m inflation with \LambdaCDM epoch
• Observational signatures of f(R) dark energy models that satisfy cosmological and local gravity constraints
• Future of the universe in modified gravitational theories: Approaching to the finite-time future singularity
• Spherically symmetric solutions in f(R)-gravity via Noether Symmetry Approach
• The Cosmology of f(R) Gravity in the Metric Variational Approach
• f(R) Gravity and Chameleon Theories
• Limit to General Relativity in f(R) theories of gravity
• Solar system and equivalence principle constraints on f(R) gravity by chameleon approach
• Modified gravity models of dark energy
• Non-singular exponential gravity: a simple theory for early- and late-time accelerated expansion
• A f(R) gravity without cosmological constant
• Spherical symmetry in $f(R)$-gravity
• Dynamical behavior in $f(T,T_G)$ cosmology
• Newton law corrections and instabilities in $f(R)$ gravity with the effective cosmological constant epoch
• Viability of f(R) Theories with Additional Powers of Curvature
• Dynamical behavior in mimetic F(R) gravity
• Autonomous Dynamical System Approach for $f(R)$ Gravity
• The phase space view of f(R) gravity
• Modified gravity as an alternative for Lambda-CDM cosmology
• Further Exact Cosmological Solutions to Higher-Order Gravity Theories
• Is exponential gravity a viable description for the whole cosmological history?
• Phase Space Analysis of the Accelerating Multi-fluid Universe
• Dynamical systems analysis of anisotropic cosmologies in $R^n$-gravity
• Crossing of the w=-1 barrier in viscous modified gravity
• Future dynamics in f(R) theories

Cited by in corpus (7)

• Cosmological models in $f(T,\mathcal{T})$ gravity and the dynamical system analysis
• Cosmology in modified $f(\mathcal{G})$ gravity: a late time cosmic phenomena
• Cosmological dynamics and observational constraints on a viable $f(Q)$ non-metric gravity model
• Analysis of the cosmological evolution parameters, energy conditions, and linear matter perturbations of an exponential-type model in $f(Q)$ gravity
• Modified gravity with disappearing cosmological constant
• Phase space analysis of an exponential model in $f(Q)$ gravity including linear dark-sector interactions
• Observational constraints on a modified-gravity model with an exponential function of the curvature using the expansion history, the RSD, and the Pantheon+SH0ES data