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RESUMEN

In this paper useful physical objects called moments of the inverse scattering operator (MISO) of the Boltzmann equation (BE) are studied. The existence and uniqueness of the MISO is proven and a simple, generally valid, iterative scheme to actually compute those objects is given. The applications of the MISO extend from the computation of the solution for the space-homogeneous BE for small electric and magnetic fields to the exact computation of any transport parameter. This can be done for all moments of the space-inhomogeneous BE and for arbitrary electric and magnetic field intensities. The concept of MISO offers an elegant way to avoid the relaxation time approximation (RTA) every time it comes into play, not only theoretically but also in practical computations.

RESUMEN

We derive a quantum mechanical correction to the semiclassical Fermi golden rule operator for scattering of electrons in a crystal. This correction takes into account the fact that electron-phonon interaction is not instantaneous in quantum mechanics. The corrective term is derived via an oscillatory, i.e., weak, limit in the Levinson equation for large timescales.