Regensburg 2025 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 31: Topology: Quantum Hall Systems

TT 31.5: Talk

Wednesday, March 19, 2025, 16:15–16:30, H31

Probing Fractional Statistics through Aharonov-Bohm Oscillations in Hanbury-Brown-Twiss Geometry — •Felix Puster, Matthias Thamm, and Bernd Rosenow — Institut für Theoretische Physik, Universität Leipzig, Brüderstraße 16, 04103 Leipzig, Germany

Since the theoretical prediction of anyonic excitations in the fractional quantum Hall effect, experimental evidence for their fractional statistics has been highly sought. In recent years, experiments have determined fractional braiding phases, providing clear evidence for fractional exchange phases. However, the braiding phase fixes the exchange phase of the particles only up to modulo Pi, leaving ambiguity in its exact value. Therefore, experiments capable of determining the exchange phase unambiguously are desired. To this end, we revisit the Hanbury-Brown-Twiss (HBT) geometry in the fractional quantum Hall regime. Our calculations extend previous theoretical work by incorporating an Aharonov-Bohm (AB) phase, finite temperature, and a finite distance between the tunneling points. We compute the current and current-current correlation functions and find that the anyonic exchange phase enters the AB oscillations in both quantities as an additive shift. While this shift is expected for the current-current correlations due to two-particle interference, for the current we interpret it as another example of time domain braiding of anyons -- a phenomenon previously reported in geometries with tunneling of anyons across a quantum point contact.

Keywords: fractional quantum Hall effect; anyonic exchange phase; Hanbury-Brown-Twiss; two-particle interference; time domain braiding