Classical and Quantum Aspects of Particle Propagation in External Gravitational Fields

In the study of covariant wave equations, linear gravity manifests itself through the metric deviation $\gamma_{\mu\nu}$ and a two-point vector potential $K_{\lambda}$ itself constructed from $\gamma_{\mu\nu}$ and its derivatives. The simultaneous presence of the two gravitational potentials is non contradictory. Particles also assume the character of quasiparticles and $K_{\lambda}$ carries information about the matter with which it interacts. We consider the influence of $K_{\lambda}$ on the dispersion relations of the particles involved, the particles' motion, quantum tunneling through a horizon, radiation, energy-momentum dissipation and flux quantization. % No {\it REVTEX} limit to number of lines.