Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 68: Correlated Electrons: (General) Theory 1
TT 68.6: Talk
Wednesday, March 18, 2015, 16:15–16:30, H 3010
Optimal bath discretization for exact diagonalization solvers of Anderson impurity models — •Malte Schüler1,2, Christian Renk1,2, and Tim Wehling1,2 — 1Institut für Theoretische Physik, Universität Bremen, Otto-Hahn-Allee 1, D-28359 Bremen, Germany — 2Bremen Center for Computational Materials Science, Universität Bremen, Am Fallturm 1a, 28359 Bremen, Germany
Exact diagonalization (ED) solvers of the Anderson impurity model (AIM) provide access to real frequency spectral properties and work in presence of arbitrarily complex Coulomb interactions, spin-orbit coupling and at low temperatures. Due to Hilbert space constrains the non-interacting bath of the AIM has however to be discretized, which is the main approximation within ED approaches and gives rise to ambiguities. We present a method which finds optimal parameters of the discretized model. Optimal means that the resulting density matrix represents the density matrix of the full model as closely as possible. This is accomplished by using a variational principle. We show benchmark results and comparisons to other discretization schemes and solvers like CT-QMC as well as first results on realistic 5-Orbital impurity models. Orbital occupancies, local spin moments and thermodynamic properties are well described within this variational ED approach.