Hybrid theory of the dynamical mean field and the spin-fluctuations in strongly correlated electron systems
نویسنده
چکیده
In order to take account of the spatial fluctuation beyond the dynamical mean field theory (DMFT), the two-particle self-consistent theory is carefully reinvestigated and is proved to be unable to reproduce the correct low energy scale in the strong correlation limit. An improved theory is proposed which starts from DMFT and is combined with the spin-fluctuation theory (SFT) in a phenomenological form. The present theory therefore encompasses DMFT and SFT, and describes the quantum critical behavior properly with the same exponent as SFT. The local quantum dynamics is fully taken into account as in DMFT in contrast to the phenomenological treatment in SFT.
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