Relative to single-band models,multiband models of strongly interacting electron systems are of growing interest because of their wider range of novel phenomena and their closer match to the electronic structure of re...Relative to single-band models,multiband models of strongly interacting electron systems are of growing interest because of their wider range of novel phenomena and their closer match to the electronic structure of real materials.In this brief review we discuss the physics of three multiband models(the three-band Hubbard,the periodic Anderson,and the Falicov-Kimball models)that was obtained by numerical simulations at zero temperature.We first give heuristic descriptions of the three principal numerical methods(the Lanczos,the density matrix renormalization group,and the constrainedpath Monte Carlo methods).We then present generalized versions of the models and discuss the measurables most often associated with them.Finally,we summarize the results of their ground state numerical studies.While each model was developed to study specific phenomena,unexpected phenomena,usually of a subtle quantum mechanical nature,are often exhibited.Just as often,the predictions of the numerical simulations differ from those of mean-field theories.展开更多
基金the Earmarked Grant for Research from the Research Grants Council(RGC)of the HKSAR,China(Project CUHK 401703)the US Department of Energywith D.S.Wang and hospitality of Institute of Physics,CAS,through grant NSFC 10329403.
文摘Relative to single-band models,multiband models of strongly interacting electron systems are of growing interest because of their wider range of novel phenomena and their closer match to the electronic structure of real materials.In this brief review we discuss the physics of three multiband models(the three-band Hubbard,the periodic Anderson,and the Falicov-Kimball models)that was obtained by numerical simulations at zero temperature.We first give heuristic descriptions of the three principal numerical methods(the Lanczos,the density matrix renormalization group,and the constrainedpath Monte Carlo methods).We then present generalized versions of the models and discuss the measurables most often associated with them.Finally,we summarize the results of their ground state numerical studies.While each model was developed to study specific phenomena,unexpected phenomena,usually of a subtle quantum mechanical nature,are often exhibited.Just as often,the predictions of the numerical simulations differ from those of mean-field theories.
