Regge trajectories of the Klein-Gordon equation with non-minimal   interaction
  A semiclassical method of deriving Regge trajectories for the bound states of the Klein-Gordon equation with the interaction introduced in a non-minimal way is proposed. The method is applied to construction of the quarkonium Regge trajectories. It is found that under the relativistic generalization of the Cornell potential the Regge trajectories of charmonium are in the same good agreement with experimental data for introducing the confinement part of potential either in the minimal, or non-minimal way. 
D. A. Kulikov, R. S. Tutik