Work

Two-particle time-domain interferometry in the fractional quantum Hall effect regime

Year: 2022

Type: article

Abstract: As with like particles in ordinary vacuum, 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 and an important challenge 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), a quantum phase displayed by two-dimensional electronic conductors in high magnetic fields. These fractionally charged quasi-particles obey anyonic statistics intermediate between fermionic and bosonic. Their quantum coherence has been observed by their transmission through the discrete localized states of electronic Fabry-Pérot interferometers [1-5]. Surprisingly, no quantum interference of anyons was observed in electronic Mach-Zehnder interferometers [6-8] for which the quasi-particle transmission occurs via propagating states forming a continuum of states. Here we address this puzzle by demonstrating that FQHE anyons do keep a finite quantum coherence while propagating along extended states by using a different kind of interferometry, namely two-particle time-domain interference [9] 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 [9], we observe strong quasi-particle interference. Visibilities as high as 53% and 60% are observed for e/5 and e/3 charged anyons propagating on the FQHE chiral edges modes. Our results give a positive message for the challenge of performing controlled quantum coherent braiding of anyons and call for a better understanding of the absence of interference in Mach-Zehnder interferometers.

Source: Nature Communications

DOI: 10.1038/s41467-022-33603-3