Quantum charge pumping through fractional Fermions in charge density modulated quantum wires and Rashba nanowires

TL;DR

This paper investigates adiabatic quantum charge pumping in systems with fractional fermionic bound states, demonstrating quantized pumped charge as a signature of these states and analyzing shot noise to confirm minimal fluctuations.

Contribution

It introduces two setups supporting fractional fermions and shows how quantum pumping reveals their presence through quantized charge and shot noise analysis.

Findings

Quantized pumped charge indicates fractional fermion states.

Minimal shot noise correlates with quantized charge transfer.

Both setups serve as signatures for fractional fermions.

Abstract

We study the phenomenon of adiabatic quantum charge pumping in systems supporting fractionally charged fermionic bound states, in two different setups. The first quantum pump setup consists of a charge-density-modulated quantum wire, and the second one is based on a semiconducting nanowire with Rashba spin-orbit interaction, in the presence of a spatially oscillating magnetic field. In both these quantum pumps transport is investigated in a N-X-N geometry, with the system of interest (X) connected to two normal-metal leads (N), and the two pumping parameters are the strengths of the effective wire-lead barriers. Pumped charge is calculated within the scattering matrix formalism. We show that quantum pumping in both setups provides a unique signature of the presence of the fractional-fermion bound states, in terms of asymptotically quantized pumped charge. Furthermore, we investigate shot noise arising due to quantum pumping, verifying that quantized pumped charge corresponds to minimal shot noise.