Dynamical Symmetry Breaking on Langevin Equation : Nambu $\cdot$   Jona-Lasinio Model
  In order to investigate dynamical symmetry breaking, we study Nambu$\cdot$Jona-Lasinio model in the large-N limit in the stochastic quantization method. Here in order to solve Langevin equation, we impose specified initial conditions and construct ``effective Langevin equation'' in the large-N limit and give the same non-perturbative results as path-integral approach gives. Moreover we discuss stability of vacuum by means of ``effective potential''. 
K. Ikegami, R. Mochizuki and K. Yoshida