Improved Composite-Boson Theory of Quantum Hall Ferromagnets and Skyrmions without Sigma Models

TL;DR

This paper introduces an improved composite-boson theoretical framework for quantum Hall ferromagnets, accurately modeling skyrmions as excitations within the lowest Landau level and matching experimental activation energy data.

Contribution

It presents a novel composite-boson approach that describes skyrmions without sigma models, focusing on physical degrees of freedom and aligning well with experimental observations.

Findings

Accurate estimation of skyrmion excitation energy

Skyrmions confined to the lowest Landau level

Good agreement with experimental activation-energy data

Abstract

We propose an improved composite-boson theory of quantum Hall ferromagnets, where the field operator describes solely the physical degrees of freedom representing the deviation from the ground state. In this scheme skyrmions appear merely as generic excitations confined in the lowest Landau level. We evaluate the excitation energy of one skyrmion. Our theoretical estimation accounts for the activation-energy data due to Schmeller et al. remarkably well.