Dynamical t/U Expansion of the Doped Hubbard Model

admin   2019-12-05 16:55:53   3008

报告题目:Dynamical t/U Expansion of the Doped Hubbard Model
报告时间:2019-12-09 15:30 (星期一)
报告地点:北洋园校区理学院32教256
报告人:丁文新 教授(安徽大学)

报告摘要: 

 We construct a new U(1) slave spin representation forthe single band Hubbard model in the large-U limit. The mean-field theory inthis representation is more amenable to describe both thespin-charge-separation physics of the Mott insulator at half-filling and thestrange metal behavior at finite doping. By employing a dynamical Green’sfunction theory for slave spins, we calculate the single-particle spectralfunction of electrons, and the result is comparable to that in dynamical meanfield theories. We then formulate a dynamical t/U expansion for the dopedHubbard model that reproduces the mean-field results at the lowest order ofexpansion. To the next order of expansion, it naturally yields an effectivelow-energy theory of a t − J model for spinons self-consistentlycoupled to an XXZ model for the slave spins. We show that the superexchange Jis renormalized by doping, in agreement with the Gutzwiller approximation.Surprisingly, we find a new ferromagnetic channel of spin-spin interactionswhich survives in the infinite U limit, as a manifestation of the Nagaokaferromagnetism.  

Ref: arXiv:1906.12071  


报告人简介: 

丁文新 博士2002年-2006年浙江大学long8唯一 2006年-2012年佛罗里达州立大学(Florida State University)与美国强磁场国家实验室(National High Magnetic Field Laboratory)博士,导师杨昆教授2012年-2015年美国莱斯大学(Rice University) 2015年-2017年美国加州大学圣克鲁兹分校(University of California, Santa Cruz)2017年-2018年中国科学院大学卡弗里理论科学研究所 主要研究方向及近期工作:1)  多体系统中量子纠缠熵的标度行为的研究。2)  t-J模型的非正则极度关联费米液体理论(extremely correlated Fermi liquid theory, ECFL)及其奇异金属相输运性质的研究。3)  量子自旋动力学系统的非正则Schwinger运动方程理论4)  强相互作用极限下的Hubbard模型的动力学理论方法及其物性研究。5)  阻挫重费米子系统的新奇量子相,相变及其物理性质的研究。   


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