How to Formulate Non-Equilibrium Local States in QFT? — General Characterization and Extension to Curved Spacetime

The essence of a general formulation to accommodate non-equilibrium local states in relativistic quantum field theory is explained from the viewpoint of comparison at a spacetime point between unknown generic states to be characterized as such states and the known family of statistical mixtures of equilibrium states. Taking advantage of the local nature of the problem, we extend the formalism to the general-relativistic context with curved spacetimes.