The Kerr medium as an {\sf SU(2)} system
  The Kerr medium in the presence of damping and associated with SU(1,1) symmetry, is solved using the techniques of Thermo field Dynamics (TFD).These TFD techniques, well studied earlier (Chaturvedi and Srinivasan, 1991), help us to exactly solve the Kerr medium as a spin damped system associated with SU(2) symmetry. Using TFD, the association with SU(2) is exploited to express the dynamics of the system as a Schrodinger-like equation, whose solution is obtained using the appropriate disentanglement theorem. These considerations are extended to a system with multi-mode coupled nonlinear oscillators." 
K. V. S. Shiv Chaitanya, Prasanta K. Panigrahi, V. Srinivasan and A.   S. Vytheeswaran
quant-ph