Restructuring Of The Group Approach To The Development And Application Of The Tj Model

With the development of the experimental technology, researchers found out that there is the obvious distinction between the experimental result and the prediction of the mean field theory on the critical phenomenon. Wilson is the first scientist who applied renormalization group method to critical phenomenon. Therefore, he opened the new frontier of the theoretical research of the critical phenomenon. Soon after that, other researchers adopt this idea to investigate critical phenomenon. They realized that the renormalization group method is a new scheme to research critical phenomenon. In the mean time, the theory of renormalization group is got developing rapidly.In the first chapter of the article, we introduced the theoretical ideas of renormalization group and primary content of the article. In the second chapter, combined with the two-dimension triangle lattice Ising model, we show the procedures of the renormalization group methods and illustrate how to apply these methods to solve critical exponent in detail. In the third chapter, connected with the cube lattice model, we present the steps of the renormalization group and indicate the corresponding relationship between the fixed points of the renormalization group and the critical points. In the forth chapter, we present the subsequent development of the renormalization group methods at the beginning. Then based upon the electron-phonon model, we explain how to apply these methods to obtain the flow equations of the model. In the fifth chapter, we present the t-J model that is an important model in the system of strongly correlated electron and high temperature superconductivity at first. Then, by using the renormalization group method, we investigate the t-J model and obtainthe elementary excitation energy spectrum of it. At last, we compare the results of renormalization group method with that of Green's functions method. Based upon these results, we conclude that the method of flow equation of the renormalization group is a good new way.