THE 4-FERMI MODEL IN 3 DIMENSIONS AT NONZERO DENSITY AND TEMPERATURE

The four-Fermi model with discrete chiral symmetry is studied in three dimensions at non-zero chemical potential and temperature using the hybrid Monte Carlo algorithm. The number of fermion flavors is chosen large (N(f) = 12) to compare with analytic results. A first order chiral symmetry restoring transition is found at zero temperature with a critical chemical potential mu(c) in good agreement with the large N(f) calculations. The critical index nu of the correlation length is measured in good agreement with analytic calculations. The two-dimensional phase diagram (chemical potential vs. temperature) is mapped out quantitatively. Finite size effects on relatively small lattices and non-zero fermion mass effects are seen to smooth out the chiral transition dramatically.