Microscopic theory of fractional excitations in gapless bilayer quantum Hall states: semi-quantized quantum Hall states

TL;DR

This paper develops a microscopic low-energy theory for semi-quantized gapless bilayer quantum Hall states, revealing their fractionalized excitations, emergent gauge fields, and unique physical properties.

Contribution

It introduces a novel theoretical framework for semi-quantized quantum Hall states, elucidating their fractional quasiparticles and emergent gauge fields.

Findings

Presence of gapless fractional charge quasiparticles

Perfect interlayer drag observed in these states

Potential to host non-Abelian anyonic excitations

Abstract

We derive the low-energy theory of semi-quantized quantum Hall states, a recently observed class of gapless bilayer fractional quantum Hall states. Our theory shows these states to feature gapless quasiparticles of fractional charge coupled to an emergent Chern-Simons gauge field. These gapless quasiparticles can be understood as composites of electrons and Laughlin-like quasiparticles. We show that semi-quantized quantum Hall states exhibit perfect interlayer drag, host non-Fermi liquid physics, and serve as versatile parent states for fully gapped topological phases hosting anyonic excitations.