May 6, 2009 Leave a comment
Department of applied mathematics and theoretical physics, University of Cambridge, silver street, Cambridge CB39EW, England
Any reasonable theory of quantum gravity will allow closed universes to branch off from our nearly flat region of space time. I describe the possible quantum states of these closed universes. They correspond to wormholes which connect to asymptotically Euclidian regions, two parts of same asymptotically regions. I calculate the influence of these wormholes on ordinary quantum field at low energies in the asymptotic region. This can be presented by adding effective interactions in flat space time which create or annihilate closed universes containing certain number of particles. The effective interactions are small except for closed universes containing scalar in the spatially homogenous mode. If these scalar interactions are not reduced by supersymmetry, it may be that any scalar particles we observe would have to be bound states of particles of high spin, such as pion . An observer in asymptotically flat region would not be able to measure the quantum state of closed universes that branched off. He would therefore have to run over all possibilities of the closed universes. This would mean that the final state would appear to be a mixed quantum state rather than a pure quantum state.