Creating and detecting poor man's Majorana bound states in interacting quantum dots

TL;DR

This paper proposes a theoretical method to create and detect poor man's Majorana bound states in a system of three interacting quantum dots with superconductivity, spin-orbit coupling, and magnetic field, enabling tunable MBS localization.

Contribution

It introduces a new setup using three quantum dots with strong interactions and superconductivity to realize and identify high-quality Majorana bound states.

Findings

High-quality MBSs can be localized on outer dots with proper tuning.

Nonlocal transport spectroscopy effectively identifies sweet spots for MBSs.

System offers a cleaner platform for studying MBS physics.

Abstract

We propose and theoretically investigate an alternative way to create the poor man's Majorana bound states (MBSs) introduced in Phys. Rev. B 86, 134528 (2012). Our proposal is based on two quantum dots (QDs) with strong electron-electron interactions that couple via a central QD with proximity-induced superconductivity. In the presence of spin-orbit coupling and a magnetic field, gate control of all three QDs allows tuning the system into sweet spots with one MBS localized on each outer dot. We quantify the quality of these MBSs and show how it depends on the Zeeman energy and interaction strength. We also show how nonlocal transport spectroscopy can be used to identify sweet spots with high MBS quality. Our results provide a path for investigating MBS physics in a setting that is free of many of the doubts and uncertainties that plague other platforms.