Gluon propagation in space-time dependent fields

The propagator for gluons in a space-time dependent field is derived. This is accomplished by solving the equation of motion for the gluonic Green's functions. Subsequently a relationship between the quark and the gluon propagator is presented. With its help characteristics of the bosonic propagator can be obtained from those of the fermionic and vice versa. Finally, this relation is discussed for the special case of ultrarelativistic collisions in the semiclassical limit.Comment: 14 pages, no figures, typos correcte

Fermion production in classical fields

The creation of quark-antiquark pairs by vacuum polarisation in the presence of classical fields is studied based on their propagators in the background. Especially the issue of gauge invariance and particularities of particle production in ultrarelativistic collider experiments are discussed.Comment: To appear in the proceedings of the 6th Conference on Strong and Electroweak Matter 2004 (SEWM04), Helsinki, Finland, 16-19 Jun 2004. 5 pages, no figure