  In a generalized Schr\"odinger picture, we consider the motion of a
relativistic particle in an external field (like in the case of a harmonic
oscillator). In this picture the analogs of the Schr\"odinger operators of the
particle are independent of both the time and the space coordinates. These
operators induce operators which are related to Killing vectors of the Anti de
Sitter (AdS) space. We also consider the nonrelativistic limit.
