108,559 research outputs found

    On the equivalence of regularization schemes

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    We illustrated via the sunset diagram that dimensional regularization 'deforms' the nonlocal contents of multi-loop diagrams with its equivalence to cut-off regularization scheme recovered only after sub-divergence were subtracted. Then we employed a differential equation approach for calculating loop diagrams to verify that dimensional regularization deformed the 'low energy' contents before subtraction. The virtues of the differential equation approach were argued especially in non-perturbative perspective.Comment: 9 pages, LaTex, no figure, revised version, new style,to appear in Comm.Theor.Phy

    Anomalous Hall effect in heavy electron materials

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    We propose a new empirical formula for the anomalous Hall effect in heavy electron materials based on a phenomenological two-fluid description of the f-electron states. The new formula incorporates two previous theories proposed by Fert and Levy in 1987 and Kontani et al. in the early 1990s and takes into account both incoherent and coherent skew scatterings from local and itinerant f-electrons. We perform experimental analysis in several heavy electron compounds and show that the new formula provides a consistent description of the evolution of the Hall coefficient in the whole temperature range down to only a few Kelvin.Comment: 6 pages, 4 figure