The hypothetical cosmic inflation, driven by a fundamental scalar field of unknown nature, is widely acclaimed as the cause of the primordial gravitational waves revealed by BICEP2 Collaboration. We challenge this opinion and suggest that the quantum vacuum enriched with the virtual gravitational dipoles (i.e. particle-antiparticle pairs with the opposite gravitational charge) might lead to a cyclic Universe, with cycles alternatively dominated by matter and antimatter and with each cycle beginning with the accelerated expansion. This scenario might have four significant advantages. First, there is no need for a mysterious scalar field. Second, there is an elegant explanation of the matter-antimatter asymmetry in the Universe: our Universe is dominated by matter because the previous cycle of the Universe was dominated by antimatter. Third, singularity and microscopic size of the universe are prevented; the new cycle of the universe is always born with a macroscopic size. Fourth, as recently argued, the virtual gravitational dipoles might also be an alternative to dark matter and dark energy.
Virtual gravitational dipoles as the cause of cosmic inflation in the beginning of each cycle of the universe