Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 4: CE: Quantum Impurities, Kondo Physics
TT 4.4: Vortrag
Montag, 22. März 2010, 11:00–11:15, H21
Spectral function of the Anderson impurity model at finite temperatures — •Aldo Isidori1, Hermann Freire2, and Peter Kopietz1 — 1Institut für Theoretische Physik, Universität Frankfurt, Max-von-Laue Strasse 1, 60438 Frankfurt, Germany — 2Instituto de Física, Universidade Federal de Goiás, 74.001-970, Goiânia-GO, Brasil
Using the functional renormalization group (FRG) and the numerical renormalization group (NRG), we calculate the spectral function of the Anderson impurity model at zero and finite temperatures. In our FRG scheme spin fluctuations are treated non-perturbatively via a suitable Hubbard-Stratonovich field, but vertex corrections are neglected. Although at zero temperature this FRG scheme does not quantitatively reproduce the known exponential narrowing of the Kondo resonance for large values of the interaction, a comparison with the numerically exact NRG results shows that the FRG gives a reasonable description of the spectral line-shape both at high energies and for temperatures larger than the Kondo scale.