Ground state of nonlinear Schrodinger systems with saturable   nonlinearity
  We prove the existence of ground state in a multidimensional nonlinear Schrodinger model of paraxial beam propagation in isotropic local media with saturable nonlinearity. Such ground states exist in the form of bright counterpropagating solitons. From the proof, a general threshold condition on the beam coupling constant for the existence of such fundamental solitons follows. 
Tai-Chia Lin, Milivoj R. Beli\'c, Milan S. Petrovi\'c and Goong Chen
math-ph math.AP math.MP