1998/09/16 by Toshihico Arimitsu, Arimitsu, Toshihico
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Theory (hep-th) #hep-th
paper · pdf · doi:10.48550/arxiv.hep-th/9809117
10 pages, The 5th International Workshop on Thermal Field Theories and Its Applications (TFT98)
arxiv created 1998/11/26 · arxiv updated 2009/11/30
Quantum field theory is constructed upon the assumption of stabilities of the vacuum and of the one-particle state. For finite temperature, the one-particle state becomes unstable because of thermal fluctuations, whereas the thermal vacuum is still stable. In non-equilibrium situation, both the vacuum and the one-particle state lose their stability. Proposed is the introduction of the \it reference vacuum which takes care of thermal and non-adiabatic time-evolution of a system, and produces a time-dependent Fock's representation space. This may provide us with an extension of the concept of \it dynamical mapping where a migration among unitary inequivalent representation spaces can be handled for non-equilibrium and dissipative systems.