  The phase diagram of the massive chiral Gross-Neveu model (the massive
Nambu-Jona-Lasinio model in 1+1 dimensions) is constructed. In the large N
limit, the Hartree-Fock approach can be used. We find numerically a chiral
crystal phase separated from a massive Fermi gas phase by a 1st order
transition. Using perturbation theory, we also construct the critical sheet
where the homogeneous phase becomes unstable in a 2nd order transition. A
tricritical curve is located. The phase diagram is mapped out as a function of
fermion mass, chemical potential and temperature and compared with the one of
the discrete chiral Gross-Neveu model. As a by-product, we illustrate the
crystal structure of matter at zero temperature for various densities and
fermion masses.
