Topics in thermo fields dynamics
Three topics in thermal quantum field theory are discussed in this thesis: the spontaneous breaking of the Lorentz-boost symmetry at finite temperature, relativistic thermodynamics, and quantum theory of an extended object at finite temperature. Thermo Field Dynamics (TFD), a thermal quantum field theory, will be used in the discussion. The existence of a heat bath breaks the Lorentz-boost symmetry at finite temperature. With TFD, this phenomenon appears in the form of a spontaneous symmetry breaking; the ground state of the system does not manifest the symmetry of the Hamiltonian. An interesting question is whether the original symmetry can disappear without trace. A physical system may manifest a symmetry different from that of the Hamiltonian without violating the invariance. The thermal breakdown of Lorentz symmetry is found to be somewhat superficial. As an application of TFD, Relativistic Thermodynamics is discussed. Balescu reviewed and clarified the situation systematically in 1968. The basic conclusion is that the generalization of equilibrium thermodynamics for a moving observer is not entirely within equilibrium thermodynamics itself and therefore a unique generalization does not exist. Balescu revived the form-invariance argument of Planck in 1908. The parallel-plate Casimir effect is studied here with a modified TFD. It lends support to the Planck argument. An attempt is made to apply TFD to quantum field with an extended object. Examples of quantal extended objects are: dislocation in crystal, domains in ferromagnets, vortices in superconductors, monoples, skyrmion, and bags in GCD. Many formalisms exist for their description. The operator QFT method studied by Umezawa, Papastamatiou and others provides an elegant approach to QFTs with or without extended objects. Since TFD generalizes a QFT without temperature (and without extended object) to one at finite temperature in a direct way, it is chosen as the tool of this study.
- Research Organization:
- Wisconsin Univ., Milwaukee, WI (United States)
- OSTI ID:
- 7015561
- Resource Relation:
- Other Information: Thesis (Ph.D.)
- Country of Publication:
- United States
- Language:
- English
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