Lattice Theoretical Approach in Strongly Correlated Electron Systems

TL;DR

This paper develops a lattice theoretical framework for strongly correlated electron systems, specifically cuprate superconductors, incorporating quantum fluctuations and reproducing key phenomena like density modulation and superconductivity.

Contribution

It introduces an effective lattice model approach that accounts for quantum fluctuations of spin Berry's phase and antiferromagnetic fluctuations in cuprates.

Findings

Reproduces density modulation, weak ferromagnetism, and superconductivity

Shows both positive and negative Hubbard models are effective under quantum fluctuations

Discusses advantages and limitations of the effective-model approach

Abstract

The effective lattice models in strongly correlated electron systems are \emph{derived} in particular for the cuprate superconductors, that incorporate the quantum fluctuations of the spin Berry's phase and the antiferromagnetic fluctuation. Consistent with the field-theoretical approach, the density modulation, the weak ferromagnetism, and the superconductivity are reproduced. We discussed the pros and cons of the effective-model approach and demonstrate that both positive and negative Hubbard model are the effective models subject to the occurrence of the quantum fluctuations of the correlation degrees of freedom.