Vacuum decay via Lorentzian wormholes

We speculate about the spacetime description due to the presence of Lorentzian wormholes (handles in space-time joining two distant regions or other universes) in quantum gravity. The semiclassical rate of production of these Lorentzian wormholes in Reissner-Nordstrom space-times is calculated as a result of the spontaneous decay of vacuum due to a real tunneling configuration. In the magnetic case it only depends on the value of the held theoretical fine structure constant. We predict that the quantum probability corresponding to the nucleation of such geodesically complete space-times should be actually negligible in our physical Universe.