Spectral densities for response functions of a marginal fermi liquid model

Abstract

The O(3) symmetric Anderson model has a Fermi liquid or marginal Fermi liquid low-energy fixed point, dependent on the parameter V 0, the hybridization matrix element to a local Majorana fermion mode. We use the numerical renormalization group method to calculate the spectral densities. For V 0=0 (non-Fermi-liquid case) there is a zero mode in the one-particle spectrum with a weight which decreases exponentially with U for large U. The scattering with this zero mode induces a | ω| low energy behavior in the single-particle response functions and a ln | ω| divergence in the dynamic spin susceptibility.