Abstract
One of the main objectives of modern cosmology is to explain the origin and evolution of cosmic structures at different scales. The principal force responsible for the formation of such structures is gravity. In a general relativistic framework, we have shown that matter density contrasts do not grow over time at scales exceeding the cosmic screening length, which corresponds to a cosmological scale of the order of two to three gigaparsecs at the present time, at which gravitational interactions exhibit an exponential cut-off. This is a purely relativistic effect. To demonstrate the suppression of density growth, we have performed N-body simulations in a box with a comoving size of 5.632 Gpc/h and obtained the power spectrum of the mass density contrast. We have shown that it becomes independent of time for scales beyond the screening length as a clear manifestation of the cosmic screening effect.