https://doi.org/10.1140/epjc/s10052-020-8114-4
Regular Article - Theoretical Physics
Modified gravity with an exponential function of curvature
Departamento de Fisica, Universidad del Valle, A.A. 25360, Cali, Colombia
* e-mail: luis.granda@correounivalle.edu.co
Received:
7
April
2020
Accepted:
1
June
2020
Published online:
15
June
2020
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 
CDM at early times and can satisfy local and cosmological constraints. It behaves as 
at 
and tends to zero at 
, 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 
.
© The Author(s), 2020
