Equivalence of light-front and conventional thermal field theory

It is shown that light front thermal field theory is equivalent to conventional thermal field theory. The proof is based on the use of spectral representations, and applies to all Lagrangians for which such equivalence has been proven at zero temperature. It is also pointed out that conventional spectral functions can be used to express light-front finite temperature free propagators. As an application of our approach, we derive the light-front finite temperature spin 1/2 fermion propagator in full Dirac space.