  We investigate quark matter at finite temperature and finite chemical
potential as an example for a relativistic many-particle quantum system.
Special relativity is realized through the front form that allows for a
Hamiltonian formulation of a statistical operator. Utilizing our previous
results we generalize the present formulation of a relativistic thermal field
theory to include a finite chemical potential. As an application we use the
Nambu-Jona-Lasinio model to investigate the gap equation and chiral
restoration.
