Dark energy, antimatter gravity and geometry of the Universe

摘要

This article is based on two hypotheses. The first one is the existence ofthe gravitational repulsion between particles and antiparticles. Consequently,virtual particle-antiparticle pairs in the quantum vacuum may be considered asgravitational dipoles. The second hypothesis is that the Universe has geometryof a four-dimensional hyper-spherical shell with thickness equal to the Comptonwavelength of a pion, which is a simple generalization of the usual geometry ofa 3-hypersphere. It is striking that these two hypotheses lead to a simplerelation for the gravitational mass density of the vacuum, which is in verygood agreement with the observed dark energy density.