# Spin and Charge Signatures of Topological Superconductivity in Rashba Nanowires

## TL;DR

This paper investigates how spin and charge signatures in Rashba nanowires serve as bulk indicators of topological superconductivity, revealing sign reversals at the topological transition that are robust against disorder.

## Contribution

It demonstrates that spin and charge sign reversals in bulk states are reliable bulk signatures of topological phase transition in Rashba nanowires, independent of Majorana fermions.

## Key findings

- Spin of bulk states reverses sign at the topological transition.
- Charge of bulk states also exhibits sign reversal at the transition.
- Signatures are robust against static disorder.

## Abstract

We consider a Rashba nanowire with proximity gap which can be brought into the topological phase by tuning external magnetic field or chemical potential. We study spin and charge of the bulk quasiparticle states when passing through the topological transition for open and closed systems. We show, analytically and numerically, that the spin of bulk states around the topological gap reverses its sign when crossing the transition due to band inversion, independent of the presence of Majorana fermions in the system. This spin reversal can be considered as a bulk signature of topological superconductivity that can be accessed experimentally. We find a similar behaviour for the charge of the bulk quasiparticle states, also exhibiting a sign reversal at the transition. We show that these signatures are robust against random static disorder.