  The ordinary Landau problem consists of describing a charged particle in
time-independent magnetic field. In the present case the problem is generalized
onto time-dependent uniform electric fields with time-dependent mass and
harmonic frequency [1].The spectrum of a Hamiltonian describing this system is
obtained. The configuration space wave functions of the model is expressed in
terms of the generalised Laguerre polynomials. To diagonalize the
time-dependent Hamiltonian we employ the Lewis-Riesenfeld method of invariants.
To this end, we introduce an unitary transformation in the framework of the
algebraic formalism to construct the invariant operator of the system and then
to obtain the exact solution of the Hamiltonian. We recover the solutions of
the ordinary Landau problem in the absence of the electric and harmonic fields,
for a constant particle mass. The quantization of this system exhibits many
symmetries such as $U(1), SU(2), SU(1,1)$. We therefore construct the
coresponding coherent states and the associated photon added and nonlinear
coherent states.
