New Cosmological Solutions of a Nonlocal Gravity Model

Symmetry

Ivan Dimitrijevic¹  Zoran Rakic¹  Branko Dragovich²  Jelena Stankovic³ 

[1] Faculty of Mathematics, University of Belgrade, Studentski Trg 16, 11158 Belgrade, Serbia;Institute of Physics, University of Belgrade, 11080 Belgrade, Serbia;Teacher Education Faculty, University of Belgrade, Kraljice Natalije 43, 11000 Belgrade, Serbia;

关键词: nonlocal gravity;    cosmological solutions;    nonsingular bounce;    cosmological constant;    cosmic radiation;    dark energy;   

DOI  :  10.3390/sym14010003

来源: DOAJ

【 摘 要 】

A nonlocal gravity model (2) was introduced and considered recently, and two exact cosmological solutions in flat space were presented. The first solution is related to some radiation effects generated by nonlocal dynamics on dark energy background, while the second one is a nonsingular time symmetric bounce. In the present paper, we investigate other possible exact cosmological solutions and find some the new ones in nonflat space. Used nonlocal gravity dynamics can change the background topology. To solve the corresponding equations of motion, we first look for a solution of the eigenvalue problem $\square (R-4\mathsf{\Lambda })=q(R-4\mathsf{\Lambda }).$ We also discuss possible extension of this model with a nonlocal operator, symmetric under $\square ⟷{\square }^{-1}$, and its connection with another interesting nonlocal gravity model.

【 授权许可】

Unknown