Excitation spectrum of Bilayer $\nu=2$ Quantum Hall Systems

TL;DR

This paper investigates the excitation spectra of bilayer quantum Hall systems at total filling factor 2 using a Hartree-Fock-Bogoliubov approach, capturing both spin and pseudospin excitations while preserving symmetry.

Contribution

It introduces a Hartree-Fock-Bogoliubov approximation that fully maintains spin rotational symmetry, enabling systematic analysis of spin-singlet and triplet excitations in bilayer quantum Hall systems.

Findings

Ground-state properties are accurately described by the approximation.

The method captures both spin-triplet and spin-singlet excitations.

Excitation spectra depend on the ground state configuration.

Abstract

Excitation spectra in bilayer quantum Hall systems at total Landau-level filling $\nu=2$ are studied by the Hartree-Fock-Bogoliubov approximation. The systems have the spin degrees of freedom in addition to the layer degrees of freedom described in terms of pseudospin. On the excitation spectra from spin-unpolarized and pseudospin-polarized ground state, this approximation fully preserves the spin rotational symmetry and thus can give not only spin-triplet but also spin-singlet excitations systematically. It is also found that the ground-state properties are well described by this approximation.