eprintid: 2105
rev_number: 9
eprint_status: archive
userid: 1
dir: disk0/00/00/21/05
datestamp: 2002-05-14 00:00:00
lastmod: 2014-04-03 11:47:49
status_changed: 2012-08-14 15:03:52
type: doctoralThesis
metadata_visibility: show
creators_name: Schütte, Albrecht
title: Hamiltonian Flow Equations and the Electron-Phonon-Problem
title_de: Flussgleichungen für Hamiltonoperatoren und das Elektron-Phonon-Problem
ispublished: pub
subjects: ddc-530
divisions: i-130300
adv_faculty: af-13
keywords: FlussgleichungenElectron-Phonon-Interaction , Superconductivity , Flow-Equations
cterms_swd: Elektron-Phonon-Wechselwirkung
cterms_swd: Supraleitung
abstract_translated_text: In this thesis we investigate the electron-phonon-system using the method of Flow Equations for Hamiltonians. In this continuous diagonalisation process the one particle energies and interaction constants are subject to a series of transformations, the ``flow'' of the Hamiltonian. They depend on a flow parameter l varying from zero to infinity. We give a proof that the asymptotic behaviour of the flow of the one-particle energies for large l is given by a constnat over squareroot of l behaviour. The constant may contain terms logarithmic in l and depends on electronic momentum k. This result is used to show that the transformation does lead to a blockdiagonal Hamiltonian decoupling the electron and the phonon subsystems.  We obtain the same renormalization of the phonon energies as Wegner and Lenz, who neglected the shift of the electronic one-particle energies. The dependency of the renormalization of the electronic energies on the distance to the fermi surface is calculated.  We investigate the transformation of the electronic one-particle operators. In the appendix we present a rigorous proof of the asymptotic behaviour. The l-dependency is changed by including an additional logarithmic factor and this refined asymptotic behaviour is investigated.
abstract_translated_lang: eng
class_scheme: pacs
class_labels: 71.38, 74
date: 2002
date_type: published
id_scheme: DOI
id_number: 10.11588/heidok.00002105
ppn_swb: 1643290525
own_urn: urn:nbn:de:bsz:16-opus-21058
date_accepted: 2002-04-17
advisor: HASH(0x55a718452630)
language: eng
bibsort: SCHUTTEALBHAMILTONIA2002
full_text_status: public
citation:   Schütte, Albrecht  (2002) Hamiltonian Flow Equations and the Electron-Phonon-Problem.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/2105/1/dissfertig.pdf