Non-Hermitian Floquet topological superconductors with multiple Majorana edge modes

TL;DR

This paper introduces a Floquet engineering method to generate multiple non-Hermitian Majorana edge modes in a one-dimensional topological superconductor, expanding the landscape of Floquet topological phases with potential quantum computing applications.

Contribution

It proposes a novel Floquet approach to produce arbitrarily many non-Hermitian Majorana modes with large topological invariants in a driven Kitaev chain.

Findings

Rich non-Hermitian Floquet topological phases identified.

Number of Majorana modes correlates with topological winding numbers.

Potential for robust Floquet topological quantum computation.

Abstract

Majorana edge modes are candidate elements of topological quantum computing. In this work, we purpose a Floquet engineering approach to generate arbitrarily many non-Hermitian Majorana zero and $\pi$ modes at the edges of a one-dimensional topological superconductor. Focusing on a Kitaev chain with periodically kicked superconducting pairings and gain/losses in the chemical potential or nearest neighbor hopping terms, we found rich non-Hermitian Floquet topological superconducting phases, which are originated from the interplay between drivings and non-Hermitian effects. Each of the phases is characterized by a pair of topological winding numbers, which can in principle take arbitrarily large integer values thanks to the applied driving fields. Under open boundary conditions, these winding numbers also predict the number of degenerate Majorana edge modes with quasienergies zero and $\pi$. Our findings thus expand the family of Floquet topological phases in non-Hermitian settings, with potential applications in realizing environmentally robust Floquet topological quantum computations.