# Probing Majorana zero modes by measuring transport through an interacting magnetic impurity

## TL;DR

This paper investigates how transport measurements through an interacting magnetic impurity can reveal the presence of Majorana zero modes at the boundary of a topological superconductor, providing robust signatures even with strong interactions.

## Contribution

It introduces an exactly solvable model showing that Majorana zero mode signatures in conductance are robust against interactions and proposes combined conductance and noise measurements to identify topological states.

## Key findings

- Half-integer zero-bias conductance $G_0=e^2/2h$ due to MZM hybridization.
- Robust MZM conductance signature persists at large interactions.
- Vanishing Fano factor $F=0$ indicates topological regime.

## Abstract

Motivated by recent experiments we consider transport across an interacting magnetic impurity coupled to the Majorana zero mode (MZM) observed at the boundary of a topological superconductor (SC). In the presence of a finite tunneling amplitude we observe hybridization of the MZM with the quantum dot, which is manifested by a half-integer zero-bias conductance $G_0=e^2/2h$ measured on the metallic contacts. The low-energy feature in the conductance drops abruptly by crossing the transition line from the topological to the non-topological superconducting regime. Differently from the in-gap Yu-Shiba-Rosinov-like bound states, which are strongly affected by the on-site impurity Coulomb repulsion, we show that the MZM signature in the conductance is robust and persists even at large values of the interaction. Interestingly, the topological regime is characterized by a vanishing Fano factor, $F=0$, induced by the MZM. Combined measurements of the conductance and the shot noise in the experimental set-up presented in the manuscript allow to detect the topological properties of the superconducting wire and to distinguish the low-energy contribution of a MZM from other possible sources of zero-bias anomaly. Despite being interacting the model is exactly solvable, which allows to have an exact characterization of the charge transport properties of the junction.