| Autor: |
Bartosch L; Institut für Theoretische Physik, Universität Frankfurt, Max-von-Laue Strasse 1, 60438 Frankfurt, Germany., Freire H, Cardenas JJ, Kopietz P |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of physics. Condensed matter : an Institute of Physics journal [J Phys Condens Matter] 2009 Jul 29; Vol. 21 (30), pp. 305602. Date of Electronic Publication: 2009 Jul 08. |
| DOI: |
10.1088/0953-8984/21/30/305602 |
| Abstrakt: |
We develop a functional renormalization group approach which describes the low-energy single-particle properties of the Anderson impurity model up to intermediate on-site interactions [Formula: see text], where Δ is the hybridization in the wide-band limit. Our method is based on a generalization of a method proposed by Schütz et al (2005 Phys. Rev. B 72 035107), using two independent Hubbard-Stratonovich fields associated with transverse and longitudinal spin fluctuations. Although we do not reproduce the exponentially small Kondo scale in the limit [Formula: see text], the spin fluctuations included in our approach remove the unphysical Stoner instability predicted by mean field theory for U>πΔ. We discuss different decoupling schemes and show that a decoupling which manifestly respects the spin-rotational invariance of the problem gives rise to the lowest quasiparticle weight. To obtain a closed flow equation for the fermionic self-energy we also propose a new scheme of truncation of the functional renormalization group flow equations using Dyson-Schwinger equations to express bosonic vertex functions in terms of fermionic ones. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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