2001/09/03 by Manuel Reenders, Reenders, Manuel
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #hep-lat #hep-ph #hep-th
paper · pdf · doi:10.48550/arxiv.hep-th/0109016
19 pp. 7 figs (REVTeX). Revised version with extended discussion and additional refs
arxiv created 2002/09/30 · arxiv updated 2009/11/30
A four-fermion model in 2+1 dimensions describing N Dirac fermions interacting via SU(N) invariant N2-1 four-fermion interactions is solved in the leading order of the 1/N expansion. The 1/N expansion corresponds to 't Hoofts topological 1/N expansion in which planar Feynman diagrams prevail. For the symmetric phase of this model, it is argued that the planar expansion corresponds to the ladder approximation. A truncated set of Schwinger-Dyson equations for the fermion propagator and composite boson propagator representing the relevant planar diagrams is solved analytically. The critical four-fermion coupling and various critical exponents are determined as functions of N. The universality class of this model turns out to be quite distinct from the Gross-Neveu model in the large N limit.