  We study the interaction between two parallel cosmic strings induced by gauge
fields and by scalar fields with non-minimal couplings to curvature. For small
deficit angles the gauge field behaves like a collection of non-minimal scalars
with a specific value for the non-minimal coupling. We check this equivalence
by computing the interaction energy between strings at first order in the
deficit angles. This result provides another physical context for the "contact
terms" which play an important role in the renormalization of black hole
entropy due to a spin-1 field.
