Adaptive tuning of Majorana fermions in a quantum dot chain

TL;DR

This paper proposes an adaptive tuning method for quantum dot chains to reliably create and detect Majorana fermions, overcoming disorder issues by controlling gate voltages and phases, with conductance measurements confirming topological states.

Contribution

It introduces an adaptive tuning algorithm for quantum dot chains to realize robust Majorana fermions, integrating resonant spectroscopy for real-time adjustments.

Findings

Achieved robust topological phases with localized Majorana states.

Demonstrated quantized zero bias conductance as proof of topological states.

Developed an adaptive tuning protocol for quantum dot systems.

Abstract

We suggest a way to overcome the obstacles that disorder and high density of states pose to the creation of unpaired Majorana fermions in one-dimensional systems. This is achieved by splitting the system into a chain of quantum dots, which are then tuned to the conditions under which the chain can be viewed as an effective Kitaev model, so that it is in a robust topological phase with well-localized Majorana states in the outermost dots. The tuning algorithm that we develop involves controlling the gate voltages and the superconducting phases. Resonant Andreev spectroscopy allows us to make the tuning adaptive, so that each pair of dots may be tuned independently of the other. The calculated quantized zero bias conductance serves then as a natural proof of the topological nature of the tuned phase.