Confinement, Spin, and QCD
  The experimental and theoretical evidence relating spin dependence and long range confinement is reviewed. One of the simplest confinement ideas, the dynamic electric flux tube picture of Buchm\"uller, can be exploited to yield a complete effective Hamiltonian. In addition to pure Thomas spin-orbit splitting the other relativistic corrections are calculated. It is shown that our effective Hamiltonian is identical to the mechanical relativistic flux tube model and gives relativistic corrections in agreement with QCD predictions. 
M. G. Olsson