Resilience of topological superconductivity under particle current

TL;DR

This paper studies how topological superconductors maintain their edge states under finite charge currents, revealing a critical current threshold and the impact on their topological classification, relevant for quantum electronics.

Contribution

It introduces a current-dependent modified Kitaev Hamiltonian and demonstrates the existence of a critical quasiparticle momentum for topological phase stability.

Findings

Existence of a finite critical quasiparticle momentum for topological phase survival

Finite current breaks time reversal symmetry and alters topological class

Topological superconductivity persists below a critical current threshold

Abstract

We investigate the robustness of topological superconductors under the perturbing influence of a finite charge current. To this aim, we introduce a modified Kitaev Hamiltonian parametrically dependent on the quasiparticle momentum induced by the current. Using different quantifiers of the topological phase, such as the Majorana polarization and the edge state quantum conditional mutual information, we prove the existence of a finite critical value of the quasiparticle momentum below which edge modes and topological superconductivity survive. We also discuss how a finite current breaks time reversal symmetry and changes the topological class in the Altland-Zirnbauer classification scheme compared to the case of isolated systems. Our findings provide a nontrivial example of the interplay between topology and the nonequilibrium physics of open quantum systems, a relation of crucial importance in the quest to a viable topological quantum electronics.