Bang or Bounce

Abstract

Following up an earlier suggestion of how the Tolman Entropy Conundrum (TEC) can be solved in a cyclic cosmology using the Come Back Empty (CBE) assumption with phantom dark energy, here we show how the same CBE strategy may work with a cosmological constant in the expansion era. As in the earlier case, this leads to a multiverse, actually an infiniverse, with the concomitant issues of predictivity and testability. Here we show how extreme flatness and homogeneity at the bounce are natural properties of the contraction era, interestingly without any necessity for an inflationary era at the beginning of the present expansion. Essential ingredients in the solution of TEC are CBE contraction and a careful treatment of what is meant by the visible universe.