An Introduction to the Brane World
  The study of the so called brane world models has introduced completely new ways of looking up on standard problems in many areas of theoretical physics. Inspired in the recent developments of string theory, the Brane World picture involves the introduction of new extra dimensions beyond the four we see, which could either be compact or even open (infinite). The sole existence of those new dimensions may have non trivial observable effects in short distance gravity experiments, as well as in our understanding of the cosmology of the early Universe, among many other issues. The goal of the present notes is to provide a short introduction to some basic aspects of the Brane World models. The discussion includes models with flat compact extra dimensions, as well as the so called Randall-Sundrum models. 
Abdel P\'erez-Lorenzana