  In this thesis we study some applications of the gauge/gravity
correspondence. In chapter 1 we introduce the gauge/gravity conjecture focusing
on the aspects that will be relevant in the rest of the work, in chapter 2 we
extend the Gubser-Klebanov-Polyakov-Witten (GKPW) prescription generalizing it
to gravity backgrounds with two boundaries. In chapter 3 we discuss the
Maldacena-Rey prescription to compute the quark-antiquark (and
monopole-antimonopole) potential in some gravity backgrounds duals to conformal
and non-conformal field theories. In particular, we analyze the stability of
the classical solutions under small fluctuations. In chapter 4 we study the
thermodynamic properties and the entanglement entropy of the 2+1 dimensional
$p$ and $p+ip$ superconductors through their dual gravity backgrounds. We
analyze the limit where the number of charged degrees of freedom is comparable
with the total number of degrees of freedom, which means that the backreaction
on the geometry due to the non-Abelian gauge field is relevant.
