Fluctuation Effect in the \pi-flux State for Undoped High-Temperature Superconductors

TL;DR

This paper investigates fluctuation effects in the pi-flux state of undoped high-temperature superconductors, revealing how fluctuations influence fermion dispersion and mass generation without additional interactions.

Contribution

It introduces a self-consistent framework for understanding fluctuation effects, mass generation, and antiferromagnetic order in the pi-flux state without extra repulsive interactions.

Findings

Fluctuations double the fermion band width.

Self-energy effects lead to dynamical mass generation.

Antiferromagnetic order emerges without additional interactions.

Abstract

The effect of fluctuations about the pi-flux mean field state for the undoped high-temperature superconductors is investigated. It is shown that fluctuations of the mean fields lead to a self-energy correction that doubles the band width of the fermion dispersion in the lowest order. The dynamical mass generation is associated with the self-energy effect due to the interaction mediated by the Lagrange multiplier field, which is introduced to impose the constraint on the fermions. A self-consistent picture about the mass generation and the prop- agation of the Lagrange multiplier field without damping is proposed. The antiferromagnetic long-range ordering is described without introducing an additional repulsive interaction. The theory suggests a natural framework to study spin disordered systems in which fermionic excitations are low-lying excitations.