Fluctuations in quantum electrodynamics with boundary conditions at finite temperature

Using standard techniques of Quantum Field Theory at finite temperature (Real-Time Technique) we determine correlation functions of observables. It turns out that for the photon field simple analytical expressions can be derived. They depend strongly on the given geometry. Its structure is reflected by the fluctuations of the electromagnetic field-strength as well as the components of the energy momentum tensor. Even though the allowed frequencies are fixed by the boundary conditions, the weight function of the spectrum is changed by the temperature. Thereby the temperature dependent contributions superpose with the zero point contributions. For the space in-between two plates the resonance structure of the zero temperature fluctuations is superposed by smooth T-dependent fluctuations. As for T = 0 for special conditions of the measuring process the fluctuations of the Casimir pressure depend on the model of the plates. The leading contributions result from the vacuum fluctuations. (orig.)Available from TIB Hannover: RA 2999(94-014) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman