Spin and charge fluctuations in the Hubbard model

TL;DR

This paper employs the strong coupling diagram technique to analyze the two-dimensional Hubbard model, revealing a four-band spectral structure linked to spin and charge fluctuations near antiferromagnetic transition.

Contribution

It introduces a method for summing ladder diagrams in the Hubbard model to study electron interactions with spin and charge fluctuations.

Findings

Observation of a four-band spectral structure at low temperatures and doping.

The four-band structure is connected to proximity to antiferromagnetic order.

The method captures the effects of spin and charge fluctuations on spectral functions.

Abstract

Using the strong coupling diagram technique for calculating the electron Green's function of the two-dimensional Hubbard model we have summed infinite sequences of ladder diagrams, which describe interactions of electrons with spin and charge fluctuations. For sufficiently low temperatures and doping a pronounced four-band structure is observed in spectral functions. Its appearance is related to the proximity of the transition to the long-range antiferromagnetic order.