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Anyon Superfluidity of Excitons in Quantum Hall Bilayers

Zhaoyu Han1, Taige Wang2, Zhihuan Dong2, Michael P. Zaletel2, and Ashvin Vishwanath1

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Phys. Rev. X 16, 021044 – Published 27 May, 2026

DOI: https://doi.org/10.1103/xs7g-dmn8

Abstract

The charged anyons of a fractional quantum Hall fluid are necessarily dispersionless due to the continuous magnetic translation symmetry. Neutral anyons, however, can disperse, resulting in a much richer space of possible “daughter” states when doped to finite density. We discuss a natural realization of such physics in quantum Hall bilayers, where a finite density of excitons with fractional statistics is argued to give rise to “anyonic exciton superfluidity,” the charge-neutral analog of anyon superconductivity. In a balanced bilayer of two Laughlin ν=1/3 states, the minimal interlayer exciton carries anyonic exchange statistics. A finite density of these excitons is argued to yield an exciton superfluid stitched to a specific bulk topological order and edge spectrum. Such a superfluidity should be most robust near the direct transition into the Halperin (112) state, and near analogous transitions in the bilayer Jain sequence at total filling νT=2×[n/(2n+1)]. These topological transitions can be described by Chern-Simons QED3, from which we derive several novel and general properties of anyon superfluidity near such transitions, including an anomalously large superfluid stiffness of κs∝|δν|1/2 at layer imbalance fraction δν. A notable feature of the phase diagrams we construct is the prevalence of spatial symmetry breaking driven by an underlying composite Fermi surface. Our results can be directly tested with currently available experimental techniques. We compare our theory with existing data and make concrete predictions for future measurements, including higher-pseudospin exciton superfluids when doping higher Jain fractions.

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Popular Summary

Characterizing the collective quantum phases formed by anyons is a primary challenge in topological physics. Quantum Hall bilayers provide a particularly promising setting since they host neutral anyons that can freely move in a strong magnetic field. We demonstrate that anyonic excitons in such systems can form an unusual superfluid phase when introduced at finite density. Our theoretical framework predicts distinct experimental signatures, such as specific transport coefficients, spatial-symmetry-breaking patterns, and the emergence of higher-charge exciton condensates at higher Jain fractions. We found that this type of superfluid is particularly robust near phase transitions between competing quantum Hall states, where the excitons exhibit reduced mass and excitation energy. These results suggest that topological criticality serves as a mechanism to enhance the stability of conducting daughter states. Our work establishes quantum Hall bilayers as a versatile platform for exploring anyonic matter and provides a guide for realizing exotic superfluid phases in strongly interacting systems.

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Phys. Rev. X 16, 021044– Published 27 May, 2026
  • Received 4 September 2025
  • Revised 17 February 2026
  • Accepted 21 April 2026
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