Quantum Pump for Fractional Charge

TL;DR

This paper proposes a theoretical method for quantized pumping of fractional charge in a fractional quantum Hall system using adiabatic modulation of couplings, with potential experimental implications.

Contribution

It introduces a novel scheme for fractional charge pumping via quasi-particle manipulation in a quantum Hall setup, emphasizing the importance of tuning the quasi-particle operator relevance.

Findings

Quantized fractional charge can be pumped by slow, periodic modulation.

Tuning the quasi-particle operator relevance is crucial for charge quantization.

The proposed setup suggests feasible experimental realization.

Abstract

We propose a theoretical scenario for pumping of fractionally charged quasi-particle in the context of $\nu=1/3$ fractional quantum Hall liquid. We consider quasi-particle pumping across an anti-dot level tuned close to the resonance. Fractional charge pumping is achieved by slow and periodic modulation of coupling of the anti-dot level to left and right moving edges of a Hall bar set-up. This is attained by periodically modulating the gate voltages controlling the couplings. In order to obtain quantization of pumped charge in the unit of the electronic charge fraction ($\nu e$) per pumping cycle in the adiabatic limit, we argue that the only possibility is to tune the quasi-particle operator to be irrelevant from being relevant in the renormalization group sense, which can be accomplished by invoking quantum Hall line junctions into the Hall bar geometry. We also comment on possibility for experimental realization of the above scenario.