  The observability of the multiverse is at the very root of its physical
significance as a scientific proposal. In this conference we present, within
the third quantization formalism, an interacting scheme between the wave
functions of different universes and analyze the effects of some particular
values of the coupling function. One of the main consequences of the
interaction between universes can be the appearance of a pre-inflationary stage
in the evolution of the universes that might leave observable consequences in
the properties of the CMB.
