Resonances for the radial Dirac operators
  We consider the radial Dirac operator with compactly supported potentials. We study resonances as the poles of scattering matrix or equivalently as the zeros of modified Fredholm determinant. We obtain the following properties of the resonances: 1) asymptotics of counting function, 2) in the massless case we get the trace formula in terms of resonances. 
Alexei Iantchenko, Evgeny Korotyaev
math.SP