Landau-Zener transitions for Majorana fermions

TL;DR

This paper investigates Landau-Zener transitions in systems with Majorana bound states, revealing a universal 50% quasiparticle production probability that could limit quantum coherence in related applications.

Contribution

It provides a numerical study of Landau-Zener transitions involving multiple Majorana bound states, highlighting a universal quasiparticle production probability.

Findings

Quasiparticle production probability is approximately 50%.

The effect is universal across different system parameters.

Potential impact on quantum coherence in Majorana-based devices.

Abstract

One-dimensional systems obtained as low-energy limits of hybrid superconductor-topological insulator devices provide means of production, transport, and destruction of Majorana bound states (MBSs) by variations of the magnetic flux. When two or more pairs of MBSs are present in the intermediate state, there is a possibility of a Landau-Zener transition, wherein even a slow variation of the flux leads to production of a quasiparticle pair. We study numerically a version of this process, with four MBSs produced and subsequently destroyed, and find that, quite universally, the probability of quasiparticle production in it is 50%. This implies that the effect may be a limiting factor in applications requiring a high degree of quantum coherence.