Numerical Renormalization Group Study of Pseudo-Fermion and Slave-Boson Spectral Functions in the Single Impurity Anderson Model

T. A. Costi; P. Schmitteckert; J. Kroha; P. Wölfle

doi:10.1103/PhysRevLett.73.1275

Numerical Renormalization Group Study of Pseudo-Fermion and Slave-Boson Spectral Functions in the Single Impurity Anderson Model

T. A. Costi, P. Schmitteckert, J. Kroha, and P. Wölfle

Phys. Rev. Lett. 73, 1275 – Published 29 August 1994

Abstract

We use the numerical renormalization group to calculate the auxiliary spectral functions of the $U = \infty$ Anderson impurity model. The slave-boson and pseudo-fermion spectral functions diverge at the threshold with exponents $α_{b}$ and $α_{f}$ given by the x-ray photoemission and the x-ray absorption exponents, respectively. In contrast to the noncrossing approximation, the exact exponents obtained here depend on the impurity occupation number. In general, vertex corrections in the convolution formulas for physical Green's functions are singular at the threshold and may not be neglected in the Fermi liquid regime.

Received 28 April 1994

DOI:https://doi.org/10.1103/PhysRevLett.73.1275

Authors & Affiliations

T. A. Costi, P. Schmitteckert^*, J. Kroha^†, and P. Wölfle

Universität Karlsruhe, Institut für Theorie der Kondensierten Materie, 76128 Karlsruhe, Germany

^*Present address: Institut für Physik, Theoretische Physik II, Universität Augsburg, 86135 Augsburg, Germany.
^†Present address: Cornell University, LASSP, Ithaca, NY 14853