English

On some integrals over the U(N) unitary group and their large N limit

Mathematical Physics 2009-09-29 v3 Condensed Matter High Energy Physics - Theory Combinatorics math.MP

Abstract

The integral over the U(N) unitary group I=DUexp\TrAUBUI=\int DU \exp\Tr A U B U^\dagger is reexamined. Various approaches and extensions are first reviewed. The second half of the paper deals with more recent developments: relation with integrable Toda lattice hierarchy, diagrammatic expansion and combinatorics, and on what they teach us on the large NN limit of logI\log I.

Keywords

Cite

@article{arxiv.math-ph/0209019,
  title  = {On some integrals over the U(N) unitary group and their large N limit},
  author = {P. Zinn-Justin and J. -B. Zuber},
  journal= {arXiv preprint arXiv:math-ph/0209019},
  year   = {2009}
}

Comments

revised: comment added in sec. 3.2