On the ground state of quantum gravity

In order to gain insight into the possible ground state of quantized Einsteinʹs gravity, we have devised a variational calculation of the energy of the quantum gravitational field in an open space, as measured by an asymptotic observer living in an asymptotically flat space-time. We find that for quantum gravity (QG) it is energetically favourable to perform its quantum fluctuations not upon flat space-time but around a “gas” of wormholes, whose size is the Planck length ap (ap≃10−33 cm). As a result, assuming such configuration to be a good approximation to the true ground state of quantum gravity, space-time, the arena of physical reality, turns out to be well described by Wheelerʹs Quantum Foam and adequately modeled by a space-time lattice with lattice constant ap, the Planck lattice.