2020/09/02 by Mudhahir Al Ajmi, Ajmi, Mudhahir Al
Physics and Astronomy · #Black Holes and Theoretical Physics #Classical mechanics #Cosmology #Cosmology and Gravitation Theories #Dark energy #De Sitter space #De Sitter universe #Einstein #FOS: Physical sciences #General Physics (physics.gen-ph) #General relativity #Mathematical physics #Metric expansion of space #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Theoretical physics #Universe #de Sitter invariant special relativity #physics.gen-ph
paper · pdf · doi:10.48550/arxiv.2009.06378
11 pages; no figures; This paper is prepaired as a Proceedings for the International Conference on Holography, String Theory and Discrete Approaches in Hanoi Phenikaa University August 3-8, 2020 Hanoi, Vietnam; Submission to SciPost at: https://scipost.org/SciPostPhysProc.202007001; Presented in the conference on 8/8/2020
openalex publication_date 2020/09/02 · arxiv created 2021/03/31 · arxiv updated 2021/04/01 · openalex created_date 2022/07/25 · openalex updated_date 2026/08/06
We consider the Einstein static and the de Sitter universe solutions and examine their instabilities in a subclass of quadratic modified theories for gravity. This modification proposed by Nash is an attempt to generalize general relativity. Interestingly, we discover that the Einstein static universe is unstable in the context of the modified gravity. In contrast to Einstein static universe, the de Sitter universe remains stable under metric perturbation up to the second order.