Berlin 2008 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 32: Correlated Electrons: Poster Session
TT 32.1: Poster
Donnerstag, 28. Februar 2008, 14:00–18:00, Poster B
Matrix product state approach for a two-lead, multi-level Anderson impurity model — •Andreas Holzner1,2, Andreas Weichselbaum2, and Jan von Delft2 — 1Institute for Theoretical Physics C, RWTH Aachen, D-52056 Aachen, Germany — 2Physics Department, Arnold Sommerfeld Center for Theoretical Physics, and Center for NanoScience, Ludwig-Maximilians-Universität München, D-80333 München, Germany
We exploit the common mathematical structure of the numerical renormalization group and the density matrix renormalization group, namely matrix product states, to implement an efficient numerical treatment of a two-lead Anderson impurity model. By adopting a star-like geometry, where each species (spin and lead) of conduction electrons is described by its own Wilson chain, instead of using a single Wilson chain for all species together, we achieve a very significant reduction in the numerical resources required to obtain reliable results. We illustrate the power of this approach by calculating some ground state properties of a four-level quantum dot coupled to two leads. The success of this proof-of-principle calculation suggests that the star geometry constitutes a promising strategy for future treatments of multi-band quantum impurity models.