large N limit

In theoretical physics, one often considers gauge theory models whose symmetries are groups of large matrices, e.g. U(N)U(N) or O(N)O(N). The limit of such theories for NN\to \infty has often remarkable properties and string-like features.

This limit is sometimes appearing in its own right, but sometimes it is just considered as an approximation for a system with fixed finite NN. One of the features is that in the large N limit is that non-planar Feynman diagrams loose their importance and that the correlation functions satisfy certain decoupling/factorization rule. The behaviour is studied in terms of expansion in 1/N1/N whose square has a simialr role to Planck constant in semiclassical approximation limit of quantum mechanics.

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  • Semyon Klevtsov, Random normal matrices, Bergman kernel and projective embeddings, arxiv/1309.7333
  • wikipedia 1/N expansion

category: physics

Last revised on September 30, 2013 at 14:57:39. See the history of this page for a list of all contributions to it.