Spin-Hamilton Operator, Graviton-Photon Coupling and an Eigenvalue   Problem
  We solve exactly the eigenvalue problem for a spin Hamilton operator describing graviton-photon coupling. Entanglement of the eigenstates are also studied. Other spin-coupled Hamilton operators involving spin-1 and spin-2 are also investigated and compared. 
Yorick Hardy and Willi-Hans Steeb
math-ph math.MP