Eran Sela | PubMed Health

PubMed2006

Fractional shot noise in the kondo regime.

Transport through quantum dots in the Kondo regime obeys an effective low-temperature theory in terms of weakly interacting quasiparticles. Despite the weakness of the interaction, we find that the backscattering current and hence the shot noise are dominated by two-quasiparticle scattering. We show that the simultaneous presence of one- and two-quasiparticle scattering results in a universal average charge 5/3e as measured by shot-noise experiments. An experimental verification of our prediction would constitute a most stringent test of the low-energy theory of the Kondo effect.

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PubMed2006

Adiabatic pumping in interacting systems.

A dc current can be pumped through an interacting system by periodically varying two independent parameters such as the magnetic field and a gate potential. We present a general expression for the adiabatic pumping current in interacting systems, written in terms of instantaneous properties of the system at equilibrium, and find the limits of its applicability. This expression generalizes the scattering approach for noninteracting particles. We apply our formula for a quantum critical system that exhibits the two-channel Kondo effect, where single particle excitations are not well defined. We find that if the quantum critical point is contained in the pumping trajectory, the pumped spin between the channels approaches h, and if it is not contained in the trajectory, the spin approaches zero when the temperature T --> 0. We discuss the non-Fermi liquid features of this system at finite T.

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