Ising Model in Phase Transition and Elementary Excitation

Ising model in phase transition, elementary excitation and percolation approach used in solid, order–disorder transition in multi-component alloys, cooperative effects and collective phenomena, and van der Waals’ gas are presented in this chapter briefly, which reveals the group actions of the system completely. Besides, Landau’s phase transition theory regulates phase transition in term of breaking of symmetry and variation of order parameters; renormalization group considers the scaling invariance of a system with infinite correlation length.