Anyon braiding and telegraph noise in a graphene interferometer.

The search for anyons, quasiparticles with fractional charge and exotic exchange statistics, has inspired decades of condensed matter research. Quantum Hall interferometers enable direct observation of the anyon braiding phase through discrete interference phase jumps when the number of encircled localized quasiparticles changes. In this study, we observed this braiding phase in both the filling factor 1/3 and 4/3 fractional quantum Hall states by probing three-state random telegraph noise (RTN) in real time. We found that the observed RTN stems from anyon quasiparticle number n fluctuations, and we reconstructed three Aharonov-Bohm oscillation signals phase shifted by 2π/3, corresponding to the three possible interference branches from braiding around n (mod 3) anyons. Our methods can be readily extended to interference of non-abelian anyons. Editor's summary: Anyons, quasiparticles that obey fractional exchange statistics, are known to emerge in fractional quantum Hall (FQH) systems. When one anyon is exchanged with another, the many-body wave function acquires a phase that can be measured using Fabry-Pérot interferometers. Werkmeister et al. used such a technique to measure this so-called braiding phase for two different filling factors in a graphene device. The researchers expect that the approach can also be used for even-denominator FQH states, where non-abelian anyons are predicted to arise. —Jelena Stajic [ABSTRACT FROM AUTHOR]