Direct detection of fractional charge in zero-field fractional states
In plain words
Quasiparticles in these fractional states should carry one third of an electron's charge, but in the zero-field states found since 2023 this has been inferred only indirectly.
Precise statement
In twisted MoTe2 or rhombohedral graphene FQAH states at $\nu = 2/3$ and $B = 0$, measure the quasiparticle charge $e*$ from the shot-noise Fano factor at a quantum point contact or from Fabry-Perot interference periods, and the braiding phase $2\pi/3$ by interferometry. An answer is $e*/e$ and the braiding phase with uncertainties.
What would settle it
Shot-noise measurement giving $e* = e/3$ and an interferometer showing $2\pi/3$ phase slips at zero applied field.
Status in the literature
Unverified note
As of 2026 only the fractional Hall conductance has been measured (transport, Streda slopes $dn/dB$, optical signatures such as arXiv:2602.04561); quasiparticle charge has not been measured by shot noise or interferometry at $B = 0$, to this survey's knowledge.