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"New Results for Random Matrix Models of QCD"

Relatore: Dr Gernot Akeman- SPhT/CEA, Saclay (France)

Aula Einstein
03 Giugno 2003 ore 16.30

Non-perturbative phenomena such as spontaneous chiral symmetry or CP breaking in QCD can be studied using low energy effective models. When taking the Goldstone bosons as the only relevant degrees of freedom the theory simplifies drastically in a particular infrared limit, becoming equivalent to a random matrix model. This limit allows to analytically predict the spectral properties of the QCD Dirac operator, containing valuable information about chiral symmetry breaking. These predictions have been largely confirmed from QCD lattice simulations and their field theoretic origin from chiral perturbation theory is understood by now. However, the introduction of a quark chemical potential has remained a challenge until very recently, for both the matrix model calculations and lattice simulations. New analytic predictions are presented for the Dirac spectrum which is now complex, as well as a comparison to QCD lattice data in the presence of a chemical potential is made.