3 research outputs found
Non-linear Dynamics in QED_3 and Non-trivial Infrared Structure
In this work we consider a coupled system of Schwinger-Dyson equations for
self-energy and vertex functions in QED_3. Using the concept of a
semi-amputated vertex function, we manage to decouple the vertex equation and
transform it in the infrared into a non-linear differential equation of
Emden-Fowler type. Its solution suggests the following picture: in the absence
of infrared cut-offs there is only a trivial infrared fixed-point structure in
the theory. However, the presence of masses, for either fermions or photons,
changes the situation drastically, leading to a mass-dependent non-trivial
infrared fixed point. In this picture a dynamical mass for the fermions is
found to be generated consistently. The non-linearity of the equations gives
rise to highly non-trivial constraints among the mass and effective (`running')
gauge coupling, which impose lower and upper bounds on the latter for dynamical
mass generation to occur. Possible implications of this to the theory of
high-temperature superconductivity are briefly discussed.Comment: 29 pages LATEX, 7 eps figures incorporated, uses axodraw style.
Discussion on the massless case (section 2) modified; no effect on
conclusions, typos correcte