A Third-Quantized Approach to the Large-N Field Models
  Large-N field systems are considered from an unusual point of view. The Hamiltonian is presented in a third-quantized form analogously to the second-quantized formulation of the quantum theory of many particles. The semiclassical approximation is applied to the third-quantized Hamiltonian. The advantages of this approach in comparison with 1/N-expansion are discussed. 
V.P.Maslov and O.Yu.Shvedov