Stability of Formation of Large Bipolaron: Nonrelativistic Quantum Field   Theory
  We are concerned with the stability of formation of large bipolaron in a 3-dimensional (3D) crystal. This problem is considered in the framework of nonrelativistic quantum field theory. Thus, the Hamiltonian formalism, as Froehlich introduced, is employed to describe the bipolaron. We approach the problem by characterizing some sufficient or necessary conditions for the bipolaron being stable. This paper gives a full detail of the author's talks at ESI, RIMS, and St. Petersburg State Univ. in 2005. 
Masao Hirokawa