Applicability of the weak coupling expansion in QCD

Recent non-perturbative investigations of renormalized couplings have produced examples of excellent precision of (weak coupling) perturbative expansions but also examples of poor asymptotic convergence. More systematic, precise and reliable investigations are needed to better understand the applicability of the perturbative expansion. In this thesis new definitions of renormalized couplings will be developed and investigated by non-perturbative Monte Carlo (MC) lattice computations.

Supervisor: Rainer Sommer (Humbolt University, Berlin)