The $q \bar{q}$ semirelativistic interaction in the Wilson loop approach

The complete $ q\bar{q}$ semirelativistic interaction is obtained as a gauge-invariant function of the Wilson loop and its functional derivatives. The approach is suitable for analytic evaluations as well as for lattice calculations. Here we consider three different models for the Wilson loop non-perturbative behaviour and discuss the related semirelativistic dynamics.