Is the Quilted Multiverse Consistent with a Thermodynamic Arrow of Time?
  Theoretical achievements, as well as much controversy, surround multiverse
theory. Various types of multiverses, with an increasing amount of complexity,
were suggested and thoroughly discussed in literature by now. While these types
are very different, they all share the same basic idea: our physical reality
consists of more than just one universe. Each universe within a possibly huge
multiverse might be slightly or even very different from the others. The
quilted multiverse is one of these types, whose uniqueness arises from the
postulate that every possible event will occur infinitely many times in
infinitely many universes. In this paper we show that the quilted multiverse is
not self-consistent due to the instability of entropy decrease under small
perturbations. We therefore propose a modified version of the quilted
multiverse which might overcome this shortcoming. It includes only those
universes where the minimal entropy occurs at the same instant of
(cosmological) time. Only these universes whose initial conditions are
fine-tuned within a small phase-space region would evolve consistently to form
their "close" states at present. A final boundary condition on the multiverse
may further lower the amount of possible, consistent universes. Finally, some
related observations regarding the many-worlds interpretation of quantum
mechanics and the emergence of classicality are discussed.
