Stability of Einstein universe against inhomogeneous perturbations in f(R, T, RμνTμν) gravity

This paper is devoted to the study of the existence and stability of the Einstein universe against scalar inhomogeneous perturbations in the background of f(R, T, Q) gravity (R, T represent the scalar curvature, trace of the energy-momentum tensor and Q = R sigma xi T sigma xi). We construct static as well as perturbed field equations using the linear equation of state in the presence of perfect fluid and examine the stability regions. Considering conserved and non-conserved cases of the energy-momentum tensor for specific models of this gravity, it is found that the stable Einstein static universe exists for both open as well as closed FRW universe models corresponding to the appropriate choice of parameters.