The Spinless Relativistic Hulth\'en Problem
  The spinless Salpeter equation can be regarded as the eigenvalue equation of a Hamiltonian that involves the relativistic kinetic energy and therefore is, in general, a nonlocal operator. Accordingly, it is hard to find solutions of this bound-state equation by exclusively analytic means. Nevertheless, a lot of tools enables us to constrain the resulting bound-state spectra rigorously. We illustrate some of these techniques for the example of the Hulth\'en potential. 
Wolfgang Lucha, Franz F. Sch\"oberl
hep-ph math-ph math.MP nucl-th quant-ph