High-Energy analysis and Levinson's theorem for the selfadjoint matrix   Schroedinger operator on the half line
  The matrix Schroedinger equation with a selfadjoint matrix potential is considered on the half line with the general selfadjoint boundary condition at the origin. When the matrix potential is integrable, the high-energy asymptotics are established for the related Jost matrix, the inverse of the Jost matrix, and the scattering matrix. Under the additional assumption that the matrix potential has a first moment, Levinson's theorem is derived, relating the number of bound states to the change in the argument of the determinant of the scattering matrix. 
Tuncay Aktosun, Ricardo Weder
math-ph math.MP