Résumé:
In this thesis, we presented the definition of the invariant theory in quantum mechanics
that allows us to treat the problems of time-dependent systems and find the solution of the Schrödinger equation. Then, we studied the time-dependent coupled oscillator of a two dimensional (2D), pointing out the errors made by the method of Hassoul et al. Next, we introduced the concepts of PT-symmetry, the pseudo-hermiticity and CPT. Finally, we have constructed the coherent states for the inverted oscillator that minimize the quantum mechanical uncertainty between the position and the momentum.