Non-perturbative renormalization of Φ-derivable approximations in theories with multiple fields

4 pages, poster contribution at the Workshop on Quark Gluon Plasma Thermalization, Vienna, August 10-12, 2005 Minor changes: added reference and definitionInternational audienceWe provide a renormalization procedure for Phi-derivable approximations in theories coupling different types of fields. We illustrate our approach on a scalar phi^4 theory coupled to fermions via a Yukawa-like interaction. The non-perturbative renormalization amounts to fixing the scalar coupling via a set of nested Bethe-Salpeter equations coupling fermions to scalars