33,063 research outputs found
The Yang Lee Edge Singularity on Feynman Diagrams
We investigate the Yang-Lee edge singularity on non-planar random graphs,
which we consider as the Feynman Diagrams of various d=0 field theories, in
order to determine the value of the edge exponent.
We consider the hard dimer model on phi3 and phi4 random graphs to test the
universality of the exponent with respect to coordination number, and the Ising
model in an external field to test its temperature independence. The results
here for generic (``thin'') random graphs provide an interesting counterpoint
to the discussion by Staudacher of these models on planar random graphs.Comment: LaTeX, 6 pages + 3 figure
Rectangular Matrix Models and Combinatorics of Colored Graphs
We present applications of rectangular matrix models to various combinatorial
problems, among which the enumeration of face-bicolored graphs with prescribed
vertex degrees, and vertex-tricolored triangulations. We also mention possible
applications to Interaction-Round-a-Face and hard-particle statistical models
defined on random lattices.Comment: 42 pages, 11 figures, tex, harvmac, eps
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