Multi-Space Structure of the Universe
  If our universe has appeared in a result of Big Bang or something like this, whether we have reasons to deny an existence of other universes appearing by the same or similar way? An objection that there is no anything like it, is doubtful, because nobody knows: what could we observe in this case? A model of a multi-space universe with mutual coupling of spaces is being proposed and investigated. 
Andrei Novikov-Borodin
physics.gen-ph