Feynman diagrams

Feynman diagrams versus Fermi-gas Feynman emulator

superstring Feynman diagrams

The multi-loop amplitudes for the closed, oriented superstring are represented by finite dimensional integrals of explicit functions calculated through the super-Schottky group parameters and interaction vertex coordinates on the supermanifold. The integration region is proposed to be consistent with the group of the local symmetries of the amplitude and with the unitarity equations. It is show...

Vertex Models on Feynman Diagrams

The statistical mechanics of spin models, such as the Ising or Potts models, on generic random graphs can be formulated economically by considering the N → 1 limit of N ×N Hermitian matrix models. In this paper we consider the N → 1 limit in complex matrix models, which describes vertex models of different sorts living on random graphs. From the graph theoretic perspective one is using matrix m...

Weight Systems from Feynman Diagrams

We find that the overall UV divergences of a renormalizable field theory with trivalent vertices fulfil a four-term relation. They thus come close to establish a weight system. This provides a first explanation of the recent successful association of renormalization theory with knot theory.

Feynman Diagrams for Stochastic Neurodynamics

We present here a method for the study of stochastic neurodynamics in the framework of the Neural Network Master Equation proposed by Cowan. We consider a model neural network composed of two{ state neurons subject to simple stochastic kinetics. We introduce a method based on Feynman diagrams to compute the moment generating function of such a network. We show that the method enables us to obta...