Switching from Crossed Andreev Reflection to Electron Teleportation via Quantum dot

TL;DR

This paper investigates how electron transport processes, specifically crossed Andreev reflection and electron teleportation, can be controlled and distinguished in a quantum dot-topological superconductor system, revealing non-local Majorana fermion properties.

Contribution

It demonstrates the switching between crossed Andreev reflection and electron teleportation in a quantum dot-topological superconductor junction based on quantum dot energy levels.

Findings

Electron can tunnel via CAR or ET depending on QD energy levels.

ET occurs when QD energies match Majorana coupling energy.

CAR occurs when QD energies are opposite and equal to Majorana coupling energy.

Abstract

We study electron transport through a normal lead-quantum dot-topological superconductor-quantum dot-normal lead (N-QD-TS-QD-N) junction. Due to the non-local nature of Majorana fermions (MFs) in the topological superconductor, there are two types of single electron transport processes in the junction: crossed Andreev reflection (CAR) and electron teleportation (ET). When the coupling energy of MFs is much larger than the coupling between MFs and QDs, electron can tunnel through topological superconductor either via CAR or ET depending on the energy levels of QDs. For instance, when both energies of QDs (labeled as $\epsilon_1$ and $\epsilon_2$) are equal to the coupling energy of MFs (denoted as $E_M$), the electron in the left lead can teleport to the right lead via MFs while when $\epsilon_1=-\epsilon_2=E_M$ is satisfied, the electron in the left lead can combine one electron in the right lead to form a cooper pair and tunnel into the topological superconductor via MFs. Since both electron teleportation and crossed Andreev reflection manifest the non-local properties of MFs, they can be used to examine the nature of MFs.