2019/07/09 by E. Elizalde, Elizalde, Emilio, Nisha Godani +3
Physics and Astronomy · Earth and Planetary Sciences · #Cosmology and Gravitation Theories #Black Holes and Theoretical Physics #Geophysics and Gravity Measurements
paper · pdf · doi:10.48550/arxiv.1907.05223
A novel function for modified gravity is proposed, f(R, T)=R+λR2+2βln(T), with constants λ and β, scalar curvature R, and the trace of stress energy tensor T, satisfying T=ρ-3p>0. Subsequently, two equations of state (EoS) parameters, namely ω and a parametric form of the Hubble parameter H, are employed in order to study the accelerated expansion and initial cosmological bounce of the corresponding universe. Hubble telescope experimental data for redshift z within the range 0.07≤ z ≤ 2.34 are used to compare the theoretical and observational values of the Hubble parameter. Moreover, it is observed that all the energy conditions are fulfilled within a neighborhood of the bouncing point t=0, what shows that the necessary condition for violation of the null energy condition, within a neighborhood of the bouncing point in general relativity, could be avoided by modifying the theory in a reasonable way. Furthermore, a large amount of negative pressure is found, which helps to understand the late time accelerated expansion phase of the universe.