o:28344 Nonlocal de Sitter gravity and its exact cosmological solutions en Abstract: This paper is devoted to a simple nonlocal de Sitter gravity model and its exact vacuum cosmological solutions. In the Einstein-Hilbert action with Λ term, we introduce nonlocality by the following way: R − 2Λ = √ R − 2Λ √ R − 2Λ → √ R − 2Λ F() √ R − 2Λ, where F() = 1+P+∞ n=1 fnn+f−n−n is an analytic function of the d’Alembert-Beltrami operator and its inverse −1 . By this way, R and Λ enter with the same form into nonlocal version as they are in the local one, and nonlocal operator F() is dimensionless. The corresponding equations of motion for gravitational field gµν are presented. The first step in finding some exact cosmological solutions is solving the equation √ R − 2Λ = q √ R − 2Λ, where q = ζΛ (ζ ∈ R) is an eigenvalue and √ R − 2Λ is an eigenfunction of the operator . We presented and discussed several exact cosmological solutions for homogeneous and isotropic universe. One of these solutions mimics effects that are usually assigned to dark matter and dark energy. Some other solutions are examples of the nonsingular bounce ones in flat, closed and open universe. There are also singular and cyclic solutions. All these cosmological solutions are a result of nonlocality and do not exist in the local de Sitter case. https://link.springer.com/article/10.1007/JHEP12(2022)054 Keywords: Classical Theories of Gravity, Cosmology of Theories BSM, Models for Dark Matte 1552099 10.1007/JHEP12(2022)054 1552101 1126-6708 2023-03-23T07:24:36.149Z 44 yes 46 Јелена Станковић Универзитет у Београду Учитељски факултет 0000-0003-2596-7827 application/pdf 628510 https://phaidrabg.bg.ac.rs/o:28344 no yes 16 70 92000001 11A42 Journal of High Energy Physics (JHEP) 2022 12 1 27 Springer [Commercial Publisher] Scuola Internazionale Superiore di Studi Avanzati (SISSA) [Co-Publisher] 2022 https://www.springer.com/journal/13130