Towards Fabry-Pérot Interferometry at ν=5/2

The fractional quantum Hall state at filling factor ν=5/2 is a leading candidate for realizing non-Abelian anyonic quasiparticles. Unlike their Abelian counterparts, braiding of non-Abelian quasiparticles does not result in a simple phase factor [J. Nakamura et al., Nature Physics 16, 931–936 (2020); J. Nakamura et al., Physical Review X 13, 041012 (2023)] but instead induces transitions between degenerate ground states. Extending Fabry–Pérot interferometry to probe these excitations presents major experimental challenges. In GaAs heterostructures, the ν=5/2 state is fragile, requiring exceptionally low disorder and high electron density to be observed. Conversely, anyon interferometry in GaAs relies on screening-well heterostructures that sharpen the confinement potential and reduce long-range Coulomb interactions. These heterostructures have proven successful for observing Abelian braiding in low-density two-dimensional electron gases. Reconciling the requirements of high density and low disorder for ν=5/2 with the screening-well design needed for Fabry–Pérot interferometry remains a central challenge. We are currently exploring multiple heterostructure designs and fabrication strategies to meet these competing demands. Preliminary results are encouraging and point towards viable pathways for extending interferometry into the non-Abelian regime.