  In this paper it is presented the model of a multiverse made up of universes
which are created in entangled pairs that conserve the total momentum
conjugated to the scale factor. For the background spacetime it is assumed a
FRW metric with a scalar field with mass $m$ minimally coupled to gravity. For
the fields that propagate in the entangled spacetimes it is considered the
perturbations of the spacetime and the scalar field, whose quantum states
become entangled too. They turn out to be in a quasi thermal state and the
corresponding thermodynamical magnitudes are computed. Three observables are
expected to be caused by the creation of the universes in entangled pairs: a
modification of the Friedmann equation because the entanglement of the
spacetimes, a modification of the effective value of the potential of the
scalar field by the backreaction of the perturbation modes, and a modification
of the spectrum of fluctuations because the thermal distribution induced by the
entanglement of the partner universes. The later would be a distinctive feature
of the creation of universes in entangled pairs.
