Equivalence between a topological and non-topological quantum dot - hybrid structures

TL;DR

This paper demonstrates an equivalence in single-electron transport properties between topological and non-topological quantum dot hybrid structures, revealing identical Fano resonances and complex Fano factors, which advances understanding of their transport behaviors.

Contribution

It establishes a theoretical equivalence between topological and non-topological quantum dot systems in terms of Fano resonances and introduces the concept of complex Fano factors as a key linking feature.

Findings

Fano resonances are identical in both systems.

The complex Fano factor qM equals qS, linking the two structures.

Superconducting phase introduces a sign change in Fano factors.

Abstract

In this work, we demonstrate an equivalence on the single-electron transport properties between systems of different nature, a topological quantum system and a (conventional) non-topological one. Our results predicts that the Fano resonances obtained in a T-shaped double quantum dot system coupled to two normal leads and one superconducting lead (QD-QD-S) are identical to the obtained in a ring system composed of a quantum dot coupled to two Majorana bound states confined at the ends of a one dimensional topological superconductor nanowire (QD-MBSs). We show that the non-zero value of the Fano (anti)resonance in the conductance of the QD-MBSs systems is due to a complex Fano factor qM , which is identical to the complex Fano factor qS of the QD-QD-S. The complex nature of qS can be understood as a sign of a phase introduced by the superconducting lead in the QD-QD-S. It is because of this phase that the equivalence between the QD-QD-S and the QD-MBSs is possible. We believe that our results can motivate further theoretical and experimental works toward the understanding of transport properties of topological quantum hybrid structures from conventional non-topological quantum systems.