Higher Energy Composite Fermion Levels in the Fractional Quantum Hall Effect

TL;DR

This paper investigates the high-energy spectrum of composite fermions in the fractional quantum Hall effect using resonant inelastic light scattering, revealing new collective modes and demonstrating the robustness of topological order.

Contribution

It provides the first direct experimental evidence of high-energy composite fermion levels, supported by theoretical calculations, expanding understanding of topological order in fractional quantum Hall systems.

Findings

Observation of numerous new collective modes

Identification of transitions across multiple composite fermion levels

Evidence for the stability of topological order at high energies

Abstract

Even though composite fermions in the fractional quantum Hall liquid are well established, it is not yet known up to what energies they remain intact. We probe the high-energy spectrum of the 1/3 liquid directly by resonant inelastic light scattering, and report the observation of a large number of new collective modes. Supported by our theoretical calculations, we associate these with transitions across two or more composite fermions levels. The formation of quasiparticle levels up to high energies is direct evidence for the robustness of topological order in the fractional quantum Hall effect.