Virginia TechWeng, Z. Y.Ting, C. S.Lee, T. K.2014-05-072014-05-071991-02Weng, Z. Y.; Ting, C. S.; Lee, T. K., "Path-integral approach to the Hubbard model," Phys. Rev. B 43, 3790(R) DOI: http://dx.doi.org/10.1103/PhysRevB.43.37900163-1829http://hdl.handle.net/10919/47872A path-integral approach to the Hubbard model is developed for the whole range of the coupling strength U. At half filling, the strong-coupling results are readily reproduced within the simple Gaussian fluctuations. The low-lying spin wave is shown to be described by the nonlinear sigma-model. The effective coupling of the doped hole with the background fluctuations also agrees with that obtained from the t-J model in the small-doping limit. At finite doping, such a formalism may provide a starting point for investigating the short-range spin-liquid state.en-USIn Copyrighthigh-tc superconductivityfield-theorysigma-modelspinantiferromagnetsstatephysics, condensed matterArticle - Refereedhttp://journals.aps.org/prb/abstract/10.1103/PhysRevB.43.3790https://doi.org/10.1103/PhysRevB.43.3790