Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 40: Poster Session Correlated Electrons
TT 40.2: Poster
Mittwoch, 13. März 2013, 15:00–19:00, Poster D
Bosonic NRG using an Optimised Basis Set of Coherent States — •Christian Kleine and Frithjof B. Anders — Technische Universität Dortmund, Lehrstuhl für Theoretische Physik II, 44221 Dortmund, Germany
The bosonic numerical renormalisation group (bNRG) has been developed to investigate the spin-boson model which exhibits a quantum phase transition between a localised and delocalised phase in the sub-ohmic regime.
Since the bNRG must always use a truncated bosonic basis set, we investigate the influence of the different choices of such finite sets onto the NRG level flow and the prediction of the
critical exponents.
We propose to use a coherent basis set close to the quantum phase transition to estimate the divergent displacements properly.
We compare the predictions for the critical coupling αc with respect to the different basis sets:
(1) standard bNRG fock space occupation eigenbase, (2) displaced oscillator occupation eigenbase and (3) coherent base.