  The role of the collective excitations as well as the free expansion dynamics
provide a key diagnostic tools for trapped Bose-Einstein condensations. Based
on such dynamics we proposed to study the relativistic version of them in the
context of a macroscopic occupation of the ground-state for spin-0 particles.
Therefore we used the Higgs model where the external trap is introduced by a
non-minimal coupling. Along with variational method, we obtained a nonlinear
coupling between dipolar and monopolar modes. Furthermore, the free expansion
is no longer ballistic reaching a relativistic confinement.
