Anomalous gravitational vacuum fluctuations which act as virtual oscillating dipoles

In this work we review some concepts developed over the last few years: that the gravitational vacuum has, even at scales much larger than the Planck length, a peculiar structure, with anomalously strong and long-lasting fluctuations called "zero-modes"; and that these vacuum fluctuations behave as virtual particles of negative mass and can interact with each other, leading to the formation of weakly bound states. The bound states make up a continuum, allowing at each point of spacetime the local excitation of the gravitational vacuum through the coupling with matter in a coherent state. The spontaneous or stimulated decay of the excited states leads to the emission of virtual gravitons with spin 1 and large p/E ratio. In this paper we also expand and discuss in physical terms several important new details concerning the zero-mode interactions, the dynamics of virtual particles with negative mass and the properties of virtual gravitons.