Can geodesics in extra dimensions solve the cosmological horizon problem?
Abstract
We demonstrate a noninflationary solution to the cosmological horizon problem in scenarios in which our observable universe is confined to three spatial dimensions (a threebrane) embedded in a higher dimensional space. A signal traveling along an extradimensional null geodesic may leave our threebrane, travel into the extra dimensions, and subsequently return to a different place on our threebrane in a shorter time than the time a signal confined to our threebrane would take. Hence, these geodesics may connect distant points which would otherwise be ``outside'' the four dimensional horizon (points not in causal contact with one another).
 Publication:

Physical Review D
 Pub Date:
 September 2000
 DOI:
 10.1103/PhysRevD.62.063513
 arXiv:
 arXiv:hepph/9910235
 Bibcode:
 2000PhRvD..62f3513C
 Keywords:

 98.80.Cq;
 Particletheory and fieldtheory models of the early Universe;
 High Energy Physics  Phenomenology;
 Astrophysics;
 High Energy Physics  Theory
 EPrint:
 9 pages, 2 figures