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"Decoherence is a necessary condition for the emergence of classical inhomogeneities and can easily be justified for amplified cosmological perturbations. However, decoherence is not sufficient to explain the breaking of translational invariance. It can be shown that as a result of unitary evolution we obtain a state which is a superposition of many macroscopically different states, each corresponding to a particular realization of galaxy distribution. Most of these realizations have the same statistical properties. Such a state is a close cosmic analog of the “Schroedinger cat.” Therefore, to pick an observed macroscopic state from the superposition we have to appeal either to Bohr’s reduction postulate or to Everett’s many-worlds interpretation of quantum mechanics. The first possibility does not look convincing in the cosmological context."

Is many-worlds the favoured interpretation in cosmology, or are there other options?