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Approximations to the QED Fermion Green's Function in a Constant External Field

S. K. J. Daniel·B. H. J. McKellar
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Abstract

An exact representation of the causal QED fermion Green's function, in an arbritrary external electromagnetic field, derived by Fried, Gabellini and McKellar, and which naturally allows for non-perturbative approximations, is here used to calculate non-perturbative approximations to the Green's function in the simple case of a constant external field. Schwinger's famous exact result is obtained as the limit as the order of the approximation approaches infinity.

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S. K. J. Daniel, B. H. J. McKellar. 2002-10-16. Approximations to the QED Fermion Green's Function in a Constant External Field. https://doi.org/10.1103/physrevd.67.033004

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