Is the Quilted Multiverse Consistent with a Thermodynamic Arrow of Time?

  Tomer Shushi [1]  ,  Yakir Aharonov [2]  ,  Eliahu Cohen [3]  
[1] Department of Physics, Ben-Gurion University of the Negev, Beersheba 8410501, Israel
[2] School of Physics and Astronomy, Tel Aviv University, Tel Aviv 6997801, Israel and Schmid College of Science, Chapman University, Orange, CA 92866, USA
[3] H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK

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 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.