Majorana edge reconstruction resolves the ν = 5/2 thermal Hall puzzle, study shows

Physicists have proposed a theoretical mechanism to reconcile experimental thermal transport observations with numerical models of the fractional quantum Hall effect at filling factor ν = 5/2, according to Proceedings of the National Academy of Sciences doi.orgProceedings of the National Academy of Sciencesdoi.orgOpen source ↗. Thermal Hall conductance κ at this plateau is quantized in half-integer multiples of κ 0 = π 2 k B 2 T / 3 h, signaling neutral Majorana edge modes associated with bulk non-Abelian anyons doi.orgProceedings of the National Academy of Sciencesdoi.orgOpen source ↗.

Previous experiments identified a half-integer value corresponding to the PH-Pfaffian topological state doi.orgProceedings of the National Academy of Sciencesdoi.orgOpen source ↗. Numerical calculations, however, consistently favor either the Pfaffian or Anti-Pfaffian configurations, creating a persistent theoretical discrepancy doi.orgProceedings of the National Academy of Sciencesdoi.orgOpen source ↗. Previous attempts to bridge this gap either required precise parameter fine-tuning or were contradicted by subsequent measurements.

To resolve the contradiction, the researchers evaluated physically realistic edges using density-matrix renormalization group simulations combined with analytic calculations of the edge structure doi.orgProceedings of the National Academy of Sciencesdoi.orgOpen source ↗. Their findings demonstrate that edge reconstruction confined strictly to the neutral Majorana sector screens the underlying bulk state doi.orgProceedings of the National Academy of Sciencesdoi.orgOpen source ↗. As a result, a bulk Pfaffian or Anti-Pfaffian system generates transport signatures identical to those of a PH-Pfaffian, providing a natural mechanism consistent with experimental data doi.orgProceedings of the National Academy of Sciencesdoi.orgOpen source ↗.