Characterizing local Majorana properties using Andreev states

TL;DR

This paper introduces a spectroscopic method using Andreev bound states to characterize Majorana zero modes in quantum-dot chains, enabling direct measurement of their properties and polarization.

Contribution

It presents a novel approach to probe Majorana modes via tunneling conductance with ABS, providing a practical tool for experimental detection and characterization.

Findings

Identifies four subgap peaks in conductance spectra related to MZMs.

Enables extraction of MZM energy splitting and coherence factors.

Provides a robust method compatible with existing setups.

Abstract

We propose using Andreev bound states (ABS) as spectroscopic probes to characterize Majorana zero modes (MZMs) in quantum-dot based minimal Kitaev chains. Specifically, we show that tunneling conductance measurements with a superconducting probe hosting an ABS reveal four subgap peaks whose voltage positions and relative heights enable extraction of the MZM energy splitting and Bogoliubov-de Gennes coherence factors. This provides direct access to zero-splitting regimes and to the local Majorana polarization - a measure of the Majorana character. The method is compatible with existing experimental architectures and remains robust in extended chains.