General Structure of Non-Equilibrium Thermo Field Dynamics

Non-equilibrium thermo field dynamics (NETFD) is constructed in a compact form upon several basic requirements (axioms) without referring to the existence of the reservoir. The dissipation is involved in NETFD through the axioms, preserving most properties of the usual quantum field theory, e.g., the operator formalism, the time-ordered formulation of the Green’s functions, the Feynman diagram method in real time. NETFD with this general and compact form appear to be fundamental in physics.