QUANTUM CHARGED SPINNING PARTICLES IN A STRONG MAGNETIC-FIELD (A QUANTAL GUIDING CENTER THEORY)

A quantal guiding centre theory is presented which allows a systematic al study of the separation of the different time scale behaviours of a quantum charged spinning particle moving in an external inhomogeneous magnetic field. A suitable set of operators adapting to the canonical structure of the problem and generalizing the kinematical momenta and guiding centre operators of a particle coupled to a homogeneous magne tic field is constructed. This allows us to rewrite the Pauli Hamilton ian as a power series in the magnetic length l(B) = root HBARc/eB maki ng the problem amenable to a perturbative analysis. The first two term s of the series are explicitly constructed. The effective adiabatic dy namics turns out to be in coupling with a gauge field and a scalar pot ential. The mechanism producing such magnetic-induced geometric-magnet ism is investigated in some detail.