Boundaries and junctions in two parity violating models in 2+1 dimensions

Recently it has been suggested that junctions between materials with different parity violating properties would be characterized by diffusion layers, analogous to those in the p-n junction. This remark is amplified by a fuller investigation of two related parity violating effective Lagrangians, which possess a kind of duality. It is shown that gauge invariance and energy conservation are sufficient to determine the behaviour at the interface. This leads to modifications of normal parity-violating electrodynamics. The coupling of an interface to an external system is a natural solution to the deficiencies of Maxwell-Chern-Simons theory. A heuristic model of a transistor-like device is discussed which relates to recent experiments in device technology. Radiative corrections to Chern-Simons theory induce a local magnetic moment interaction whose lagrangian is everywhere gauge invariant. The effects of this interaction are compared to Maxwell-Chern-Simons theory. The dispersion of classical waves for these models is computed and the laws of reflection and refraction are found to hold despite the lack of $P$ and $T$ invariance. The magnetic moment dispersion is gapless in contrast to the Chern-Simons dispersion except in the case of a scalar field which is covariantly constant. Both models exhibit optical activity (Faraday effect).