German Title: Dissipative Quantensysteme und Flussgleichungen
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Translation of abstract (English)
This work investigates dissipative quantum systems by means of Flow Equations for Hamiltonians. We start with the Spin-Boson Model including one bosonic mode. The Flow Equation results for the ground-state energy and for the transformation of the Pauli spin matrices are compared with the numerically exact solution. For the Spin-Boson Model with an arbitrary number of bosonic modes and explicitly broken reflection symmetry, general Flow Equations are set up using a truncation scheme which involves an l-dependent normal ordering procedure. Furthermore, observations on universal asymptotic behaviour are discussed. The remaining chapter investigates quantum Brownian motion in a periodic potential with broken reflection symmetry - employing the previous procedures. In this context we also include results for the Tomonaga-Luttinger Model with impurity.
Document type: | Dissertation |
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Supervisor: | Mielke, Prof. Dr. Andreas |
Date of thesis defense: | 20 February 2002 |
Date Deposited: | 27 Feb 2002 00:00 |
Date: | 2002 |
Faculties / Institutes: | The Faculty of Physics and Astronomy > Institute for Theoretical Physics |
DDC-classification: | 530 Physics |
Controlled Keywords: | Dissipation, Brownsche Bewegung, Magnetische Phasenumwandlung, Renormierungsgruppe, Feldtheorie |
Uncontrolled Keywords: | Flussgleichung , Spin-Boson-Modell , Rauschinduzierter Transportflow equation , spin-boson model , noise induced transport |