Cj. Burden et Pc. Tjiang, DECONSTRUCTING THE VERTEX ANSATZ IN 3-DIMENSIONAL QUANTUM ELECTRODYNAMICS - ART. NO. 085019, Physical review. D. Particles and fields, 5808(8), 1998, pp. 5019
We consider the problem of designing an Ansatz for the fermion-photon
vertex function, using three-dimensional quantum electrodynamics as a
test case. In many existing studies, restrictions have been placed on
the form of the vertex Ansatz by making the unsubstantiated assumption
that in the quenched, massless limit the Landau gauge Dyson-Schwinger
equations admit a trivial solution. We demonstrate, without recourse
to this assumption, the existence of a nonlocal gauge in which the fer
mion propagator is the bare propagator. This result is used to provide
a viable Ansatz for part of the vertex function. [S0556-2821 (98)0022
0-3].