Exact Nonequilibrium Dc Shot-Noise In Luttinger Liquids And Fractional Quantum Hall Devices

A point contact in a Luttinger liquid couples left- and right-moving channels, producing shot noise. We calculate exactly the de shot noise at zero temperature in the out-of-equilibrium steady state where current is flowing. Integrability ensures the existence of a quasiparticle basis where scattering is ''one by one'' off the point contact, enabling us to generalize the Landauer approach to shot noise to this interacting model. Experiments in a fractional quantum Hall effect device should test our results, providing a clear signal of the fractional charge of the Laughlin quasiparticles.