Cosmology on a gravitational wave background

Abstract

ABSTRACT It is a fact that the universe lives on a gravitational wave background (GWB), which is extra space–time energy that is not contained in Einstein’s field equations. In a previous work, this energy is treated as a property of space–time and not as a source. With this in mind, a new model was developed that incorporates this energy to explain the current accelerated expansion of the universe where the GWB was incorporated by extending Einstein’s equations to $R_{\mu \nu }-\frac{1}{2}Rg_{\mu \nu }+\frac{2\pi ^2}{{\lambda }^2}g_{\mu \nu }= \kappa ^2 T_{\mu \nu }$, where λ is the Compton wavelength of the cosmological scale graviton. In the present work, we show that this extended form agrees very well with the observations of cosmic chronometers, baryon acoustic oscillations, and Pantheon SN Type Ia, reproducing the observational data with a Δχ2 = 3.26 in favour of the current model compared to the ΛCDM. The favoured values by these observations are Ω0m = 0.311 ± 0.065, H0 = 68.3 ± 1.4 km s−1 Mpc−1, and Ω0k = 0.001 ± 0.011. We also find excellent agreement of this model with the cosmic microwave background and the mass power spectrum. We conclude that this model is an excellent alternative to explain the accelerated expansion of the universe without incorporating the cosmological constant or any type of extra matter.