Some problems on macroscopic quantum phenomena and josephson junctions
"This thesis contains basically two parts. In the' first part, the theory of quantum dynamics of a general particle in fermionic heat baths is considerd. In contrast to the existing work in the literature, we employ a path. integral formalism with fermions being treated in Grassmann algebra. Working on this formalism, we are able to investigate many interesting systems. Our main goal is on the mapping between fermion baths and boson baths. Two major methods are used respectively, and the mapping has been achieved in several practically important cases. The second pari is concemed with the experimental test of macroscopic quantum phenomena in systems of Josephson junc-tion(s). In trying to determine in general the parameters of Josephson junction (this determination is essential for the test), we investigate the bottom pan of the ""returnI- V characterisiic of a current-biassed junction. We show that this investigation can indeed lead. to a q~titative determination of the parametel""B. Moreover, we a1so study an imporlant phenomenon associa.ted with the problem, the quantum (as well as classical) fluctuation-induced retrapping, and interesting predictions have been made."
macroscopic quantum phenomena, Josephson junctions, quantum dynamics
University of Illinois - Urbana-Champaign
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