Magnetic phase diagram of the Hubbard model

TL;DR

This paper investigates the magnetic phase diagram of the infinite-dimensional Hubbard model, comparing quantum Monte Carlo results with strong and weak coupling theories, revealing the importance of quantum fluctuations and limitations of strong-coupling approaches.

Contribution

It provides a detailed analysis of the magnetic phases in the Hubbard model using advanced simulation and approximation methods, highlighting the effects of quantum fluctuations.

Findings

Quantum fluctuations significantly alter the weak-coupling phase diagram.

Quantum Monte Carlo results show remarkable agreement with weak-coupling approximations.

Strong-coupling theories exhibit pathological behavior and are less reliable.

Abstract

The competition between commensurate and incommensurate spin-density-wave phases in the infinite-dimensional single-band Hubbard model is examined with quantum Monte Carlo simulation and strong and weak coupling approximations. Quantum fluctuations modify the weak-coupling phase diagram by factors of order unity and produce remarkable agreement with the quantum Monte Carlo data, but strong-coupling theories (that map onto effective Falicov-Kimball models) display pathological behavior. The single-band model can be used to describe much of the experimental data in Cr and its dilute alloys with V and Mn.