The quantum-field vacuum model of dark energy

The gravitational mechanism of the radical reduction, comparing with the predictions of the local quantum field theory, of physical vacuum energy density is considered. It is shown that the account of self-gravitation of the quantum vacuum fluctuations decreases the total energy of fluctuations of the Planck size to zero, transforming them in topologically closed configurations. The total energy is defined as the positive self-energy of fluctuation plus the negative energy of its self-gravitation. By reasons of statistical physics, a hypothesis about the crystal-like ordering of the whole system of massless 'Planck cells' is suggested. In this massless (or almost massless) crystal-like structure the subsystem of vacuum condensates with positive energy is integrated. The condition for the topological closure of Universe allows us to obtain an upper bound for positive energy density in the system close to the currently observed value.