Fractionally charged quasiparticles

Fractionally charged quasiparticles were proposed by Laughlin to explain the fractional quantum Hall effect. Flowing in one-dimensional-like strips along the edges of the sample the quasiparticles are expected to condense to a chiral Luttinger liquid (CLL). Adding a backscattering impurity in the path of the quasiparticles induces correlation among the scattering events at sufficiently low temperatures, hence leading to highly non-linear I–V characteristic and non-Poissonian shot noise. Moreover, a sufficiently strong backscatterer induces bunching of the backscattered quasiparticles with a super Poissonian shot noise corresponding to stochastic transfer of electrons. Diluting the impinging quasiparticle beam mimics an increased temperature. For example, correlation among scattering events in dilute beams relaxes and bunching ceased altogether. At finite temperature and fractionally charged quasiparticles are found to traverse almost opaque barriers. Turning to the extremely low-temperature regime (View the MathML source) we found unexpected results. At higher order fractions, ν=p/m with p>1, and very weak backscattering potential a spontaneous bunching of quasiparticles to q=νe took place, namely, at ν=2/5, q=2e/5 and at ν=3/7, q∼3e/7. As the temperature increases bunching ceased and the scattered charge was again the familiar Laughlinʹs quasiparticle q=e/m independent of p.