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Toward a systematic 1/d expansion: Two particle properties

Gergely Zarand·Daniel L. Cox·Avraham Schiller
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Abstract

We present a procedure to calculate 1/d corrections to the two-particle properties around the infinite dimensional dynamical mean field limit. Our method is based on a modified version of the scheme of Ref. onlinecite{SchillerIngersent}}. To test our method we study the Hubbard model at half filling within the fluctuation exchange approximation (FLEX), a selfconsistent generalization of iterative perturbation theory. Apart from the inherent unstabilities of FLEX, our method is stable and results in causal solutions. We find that 1/d corrections to the local approximation are relatively small in the Hubbard model.

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Gergely Zarand, Daniel L. Cox, Avraham Schiller. 2000-02-04. Toward a systematic 1/d expansion: Two particle properties. https://doi.org/10.1103/physrevb.62.r16227

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