The Gross-Neveu model from string theory

We study an intersecting D-brane model which at low energies describes (1 + 1)-dimensional chiral fermions localized at defects on a stack of N-c D4-branes. Fermions at different defects interact via exchange of massless (4 + 1)-dimensional fields. At weak coupling this interaction gives rise to the Gross-Neveu (GN) model and can be studied using field theoretic techniques. At strong coupling one can describe the system in terms of probe branes propagating in a curved background in string theory. The chiral symmetry is dynamically broken at zero temperature and is restored above a critical temperature T-c which depends on the coupling. The phase transition at T-c is first order at strong coupling and second order at weak coupling. (c) 2007 Elsevier B.V. All rights reserved.