Physical Review A
Algebraic time-ordering techniques and harmonic oscillator with time-dependent frequency
G. Dattoli, S. Solimeno, A. Torre
Abstract
The Wei-Norman algebraic techniques for time-ordering problems are applied to the study of the evolution of quantum states ruled by a harmonic-oscillator Hamiltonian with a time-dependent frequency. The slowly varying frequency case is studied; the adiabatic theorem is rederived together with higher-order corrections. The analogy with the propagation of a paraxial beam through a self-focusing fiber is also pointed out.