Field theoretical approach to spin models  

作　　者：Feng Liu Zhenhao Fan Zhipeng Sun Xuzong Chen Dingping Li 

机构地区：[1]School of Physics,Peking University,Beijing 100871,China [2]Collaborative Innovation Center of Quantum Matter,Beijing 100871,China [3]School of Electronics Engineering and Computer Science,Peking University,Beijing 100871,China

出　　处：《Frontiers of physics》2021年第6期109-115,共7页物理学前沿（英文版）

基　　金：The work was supported by the National Natural Science Foundation of China(Grant Nos.11674007,91736208,and 11920101004)。

摘　　要：We developed a systematic non-perturbative method base on Dyson–Schwinger theory and theΦ-derivable theory for Ising model at broken phase.Based on these methods,we obtain critical temperature and spin spin correlation beyond mean field theory.The spectrum of Green function obtained from our methods become gapless at critical point,so the susceptibility become divergent at Tc.The critical temperature of Ising model obtained from this method is fairly good in comparison with other non-cluster methods.It is straightforward to extend this method to more complicate spin models for example with continue symmetry.

关 键 词：Ising model mean field theory Dyson–Schwinger equations 

分 类 号：O17[理学—数学] O4[理学—基础数学]