Vacuum structure and the arrow of time
Abstract
We find ourselves in an extended era of entropy production. Unlike most other observations, the arrow of time is usually regarded as a constraint on initial conditions. I argue, however, that it primarily constrains the vacuum structure of the theory. I exhibit simple scalar field potentials in which lowentropy initial conditions are not necessary, or not sufficient, for an arrow of time to arise. In particular, in some models an arrow of time obtains even if the initial vacuum has arbitrarily large entropy. In such examples, the dynamical resolution of the arrow of time problem arises from properties of the vacuum structure similar to those that allow the string landscape to solve the cosmological constant problem without producing an empty universe, particularly its high dimensionality and the large difference in vacuum energy between neighboring vacua.
 Publication:

Physical Review D
 Pub Date:
 December 2012
 DOI:
 10.1103/PhysRevD.86.123509
 arXiv:
 arXiv:1112.3341
 Bibcode:
 2012PhRvD..86l3509B
 Keywords:

 98.80.k;
 Cosmology;
 High Energy Physics  Theory;
 Astrophysics  Cosmology and Extragalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 31 pages JHEP format, 3 figures