Zur Quantentheorie der Transportprozesse im Magnetfeld. I

A system of free electrons and fixed scatterers with spatially varying temperature and chemical potential in the presence of electric and magnetic fields is considered. Starting from the quantum-mechanical Liouville equation a simple derivation of the Kubo formulae for the transport coefficients is given. Their antisymmetric part has to be completed by the contribution of the local equilibrium density operator, similarly to the case of the steady diffusion considered by Nakajima. Using a damping theoretical expansion a generalized transport equation is obtained which takes account of the action of the external electric field and the gradient of the temperature and the chemical potential during the collisions (interference effect).