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Elad Shopen

Publications and source records attributed to Elad Shopen.

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Quasi-particle Tunneling Through a Barrier in the Fractional Quantum Hall Regime

Tunneling of fractionally charged quasi-particles (QPs) through a barrier is considered in the context of a multiply connected geometry. In this geometry global constraints do not prohibit such a tunneling process. The tunneling amplitude is evaluated and the crossover from mesoscopic QP-dominated to electron-dominated tunneling as the system's size is increased is found. The presence of disorder enhances both electron and QP tunneling rates.

cond-mat.mes-hall

Can Quasi-Particles Tunnel Through A Barrier?

This is a qualitative description of a systematic analysis carried out by us. We address the question of whether fractionally charged particles, in the context of the fractional quantum Hall effect (FQHE) can tunnel through a potential barrier (around which the density of the quantum Hall liquid is practically zero). Setting the barrier in a multiply-connected FQHE geometry removes the "global constraint" which prohibits such tunnelling. We have performed a microscopic analysis of adiabatic charge pumping and tunnelling in a torus geometry. Below we summarize our analysis in semi-qualitative terms. We also propose a setup-- different from the torus geometry-- amenable to experimental verification.

cond-mat.mes-hall

Enhancement of quantum dot peak-spacing fluctuations in the fractional q uantum Hall regime

The fluctuations in the spacing of the tunneling resonances through a quantum dot have been studied in the quantum Hall regime. Using the fact that the ground-state of the system is described very well by the Laughlin wavefunction, we were able to determine accurately, via classical Monte Carlo calculations, the amplitude and distribution of the peak-spacing fluctuations. Our results clearly demonstrate a big enhancement of the fluctuations as the importance of the electronic correlations increases, namely as the density decreases and filling factor becomes smaller. We also find that the distribution of the fluctuations approaches a Gaussian with increasing density of random potentials.

cond-mat.mes-hall