The Lattice NJL Model at Non-zero Baryon and Isospin Densities

Abstract

We present initial results of a numerical investigation of the chiral symmetry restoring transition in the (3+1)-dimensional Nambu -- Jona-Lasinio model with both non-zero baryon chemical potential (mu_B) and isospin chemical potential (mu_I). With non-zero isospin chemical potential, the model suffers from a sign problem. We proceed in two ways: (i) We perform ``partially quenched'' simulations in which mu_I is made non-zero only during the measurement of chiral observables; (ii) We perform full simulations with imaginary isospin chemical potential with the aim to analytically continue results to real mu_I.

Comments: 3 pages, 3 figures, poster presented at LATTICE 2004, Fermi National Accelerator Laboratory, June 21-26, 2004