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TT: Fachverband Tiefe Temperaturen
TT 32: Correlated Electrons: Poster Session
TT 32.44: Poster
Thursday, February 28, 2008, 14:00–18:00, Poster B
Boson-controlled quantum transport — •Holger Fehske1, Andreas Alvermann1, Gerhard Wellein2, and David M. Edwards3 — 1Ernst Moritz Arndt Universität Greifswald, Greifswald, Germany — 2Universität Erlangen-Nürnberg, Erlangen, Germany — 3Imperial College London, London, United Kingdom
We investigate transport within some background medium by means of an effective lattice model with a novel form of fermion-boson coupling. The bosons correspond to local fluctuations of the background. The model captures the principal transport mechanisms that apply to a great variety of physical systems, and can be applied to describe the motion of lattice and spin polarons, or the dynamics of a particle coupled to a bath. Performing large-scale numerical simulations based on highly efficient variational Lanczos and Chebyshev moment expansion techniques, we analyse the newly proposed model by exactly calculating the single quasiparticle effective mass, ground-state dispersion and spectral function, as well as the Drude weight and the optical conductivity for an infinite one-dimensional system. For the half-filled band case, we establish a metal-insulator quantum phase transition by analysing the particle-particle and particle-boson correlations and photoemission spectra.