Continuous-Time Quantum Monte Carlo Study of Local Non-Fermi Liquid State in the Multichannel Anderson Model

TL;DR

This study uses continuous-time quantum Monte Carlo to analyze the local non-Fermi liquid state in the multichannel Anderson model, revealing specific spectral and self-energy behaviors characteristic of non-Fermi liquids.

Contribution

It extends the quantum Monte Carlo method to the multichannel Anderson model to evaluate the impurity Green's function in the non-Fermi liquid state.

Findings

Gf exhibits a |w|^{1/2} dependence at low frequencies

Zero-frequency Green's function c depends only on N

Self-energy has resonance and non-Fermi liquid components

Abstract

The impurity Green's function Gf in the local non-Fermi liquid state is evaluated by means of the continuous-time quantum Monte Carlo method extended to the multichannel Anderson model. For N=M (where N and M are numbers of spin components and channels, respectively), Gf is expressed as -Im Gf(w+i0) = c - b |w|^{1/2}, and the zero-frequency value c depends only on N (=M). A corresponding impurity self-energy at low frequencies is composed of two parts: a resonance term related to c, and a non-Fermi liquid term proportional to |w|^{1/2}. The characteristic energy scale is discussed in terms of the non-Fermi liquid term in the self-energy.