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 decreasing present in the integer case for not too strong interactions. This feature allows 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.