Hydrodynamic vacuum sources of dark matter self-generation in an accelerating universe without a Big Bang

Abstract

We have obtained a generalization of the hydrodynamic theory of vacuum in the context of general relativity. While retaining the Lagrangian character of general relativity, the new theory provides a natural alternative to the view that the singularity is inevitable in general relativity and in the theory of a hot Universe. We show that the macroscopic source-sink motion of the ordinary (dark) matter during production-absorption of particles by vacuum generates polarization (determining the variability of the cosmological term in general relativity). We have removed the well-known problems of the cosmological constant by refining the physical nature of dark energy associated precisely with this hydrodynamically initiated variability of the vacuum energy density. A new exact solution of the modified general relativity equations that contains no free (fitting) parameter (additional to thouse available in general relativity) has been obtained. It corresponds to continuous and metric-affecting production of ultralight dark matter particles out of vacuum, with its density being retaned constant during the expansion of spatially flat Universe. This solution is shown to be stable in the regime of cosmological expansion untill Tmax about 38 billion years. After that time, the solution becomes unstable and characterizes the inverse process of dark matter particles absorption by the vacuum in the regime of contraction of the Universe. The physical nature of dark matter particles is considered and their mass is estimated. Good quantitative agreement of the indicated exact solution with cosmological observations (SnIa, SDSS-BAO and recently found reduction of acceleration of the expanding Universe) has been obtained.