The half-filled Landau level - composite fermions and dipoles

TL;DR

This paper reviews and extends the composite fermion approach at half-filled Landau levels, emphasizing the role of electrically neutral dipolar quasiparticles and their behavior near filling factor 1/2.

Contribution

It introduces an extension of the dipolar quasiparticle framework to filling factors near 1/2, incorporating both dipole moments and charge.

Findings

Quasiparticles at filling factor 1/2 are electrically neutral with dipole moments.

The electron-centered quasiparticle approach can be extended to nearby filling factors.

The extended framework accounts for both dipole moments and charge of quasiparticles.

Abstract

The composite-fermion approach as formulated in the fermion Chern-Simons theory has been very successful in describing the physics of the lowest Landau level near Landau level filling factor 1/2. Recent work has emphasized the fact that the true quasiparticles at these filling factors are electrically neutral and carry an electric dipole moment. In a previous work, we discussed at length two formulations in terms of dipolar quasiparticles. Here we briefly review one approach - termed electron-centered quasiparticles - and show how it can be extended from 1/2 to nearby filling factors where the quasiparticles carry both an electric dipole moment and an overall charge.