Two-particle time-domain interferometry in the Fractional Quantum Hall Effect regime

Quasi-particles are elementary excitations of the ground state of condensed matter quantum phases. Demonstrating that they keep quantum coherence while propagating is a fundamental issue for their manipulation for quantum information tasks. This is particularly the case for the quasi-particles called anyons of the Fractional Quantum Hall Effect (FQHE). These fractionally charged quasi-particles obey anyonic statistics intermediate between fermionic and bosonic. Their quantum coherence has been observed by their transmission through the localized states of electronic Fabry-Pérot interferometers. Surprisingly, no or very weak quantum interference of anyons was observed in electronic Mach-Zehnder interferometers for which the quasi-particle transmission occurs via propagating states. Here, we show that FQHE anyons do keep a finite quantum coherence while propagating by using a novel kind of interferometry, namely two-particle time-domain interference [1] using an electronic beam-splitter. By varying the time delay between photo-created electron-hole pairs and measuring cross-correlated noise sensitive to the two-particle Hanbury Brown Twiss (HBT) phase [1], we observe strong quasiparticle interference [2]. At bulk filling factor 2/5, visibilities as high as 53% and 60% are observed for e/5 and e/3 charged propagating anyons, probably limited by co-propagating channel mixing [3]. At bulk filling factor 2/3 a similar large quantum coherence is observed for the 2/3 edge channel.

Our results [2] call for a better understanding of anyon coherence in the FQHE edge channels.

[1] V. S. Rychkov, M. L. Polianski, and M. Büttiker, Phys. Rev. B 72, 155326 (2005)

[2] I. Taktak, M. Kapfer, J. Nath, P. Roulleau, M. Acciai, J. Splettstoesser, I. Farrer, D. A.

Ritchie, D. C. Glattli, To appear in NATURE COMM. (2022). Also at: arXiv:2201.09553 (2022)

[3] Matteo Acciai, Preden Roulleau, D. Christian Glattli, Imen Taktak, Janine Splettstoesser, Phys. Rev. B 105, 125415 (2022) ; arXiv:2201.06833 (2022)