Current enhancement through a time-dependent constriction in fractional topological insulators

We analyze the backscattering current induced by a time-dependent constriction as a tool to probe fractional topological insulators. We demonstrate an enhancement of the total current for a fractional topological insulator induced by the dominant tunneling excitation, contrary to the decrease present in the integer case for not too strong interactions. This feature allows us to unambiguously identify fractional quasiparticles. Furthermore, the dominant tunneling processes, which may involve one or two quasiparticles depending on the interactions, can be clearly determined.