Bound states in the continuum poisoned by Majorana fermions

TL;DR

This paper investigates how Majorana bound states influence the formation of bound states in the continuum within a triple quantum dot system coupled to topological superconductors, revealing conditions for their emergence and potential for protection using gate voltages.

Contribution

It introduces a novel analysis of BICs affected by MBSs in a quantum dot-topological superconductor system, highlighting the role of inter MBSs coupling and gate voltages.

Findings

BICs form with topological features due to MBSs presence.

BICs are absent in long wire limit with zero inter MBSs coupling.

BICs appear in electronic transmission when inter MBSs couplings are non-zero.

Abstract

In this work, we study the bound states in the continuum (BICs) in a system formed by a triple quantum dot array embedded between two one-dimensional topological superconductors, both hosting Majorana bound states (MBSs) at its ends. The results show the formation of BICs with topological characteristics due to the presence of MBSs. The latter is a consequence of the interplay between the BIC arising from quantum dots states by means of energy level symmetry breaking through gate voltages, and MBSs leaked into the quantum dots. The BIC is not observed when both TSCs are in long wire limit, i. e. for vanishing inter MBSs coupling, while it projects into the electronic transmission whenever the inter MBSs couplings are away from zero, regardless if they are different and/or the phase difference between both TSCs. We study the behavior of BICs poisoned by MBSs as a function of the parameters that are controlling the system. We believe our findings could be useful to implement a protection tool for BICs using MBSs based on tunable gate voltages.