New Approximations to the Fradkin representation for Green's functions

1997/06/19 by Predrag Stojkov, Stojkov, Predrag L.
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Experimental and Theoretical Physics Studies #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #Quantum, superfluid, helium dynamics

paper · pdf · doi:10.48550/arxiv.hep-th/9706135

openalex publication_date 1997/06/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

A new variant of the exact Fradkin representation of the Green's function G_c(x,y|gU), defined for arbitrary external potential U, is presented. Although this new approach is very similar in spirit to that previously derived by Fried and Gabellini, for certain calculations this specific variant, with its prescribed approximations, is more readily utilizable. Application of the simplest of these forms is made to the λΦ⁴ theory in four dimensions. As an independent check of these approximate forms, an improved version of the Schwinger-DeWitt asymptotic expansion of parametrix function is derived.

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