  We show that the adiabatic motion of ultra-cold, multi-level atoms in
spatially varying laser fields can give rise to effective non-Abelian gauge
fields if degenerate adiabatic eigenstates of the atom-laser interaction exist.
A pair of such degenerate dark states emerges e.g. if laser fields couple three
internal states of an atom to a fourth common one under pairwise
two--photon-resonance conditions. For this so-called tripod scheme we derive
general conditions for truly non-Abelian gauge potentials and discuss special
examples. In particular we show that using orthogonal laser beams with orbital
angular momentum an effective magnetic field can be generated that has a
monopole component.
