# Mechanical analogue of a Majorana bound state

## TL;DR

This paper demonstrates a mechanical analogue of a Majorana bound state by creating a topologically protected, non-propagating state in a 2D mechanical honeycomb lattice through a Kekulé distortion vortex, expanding topological concepts to bosonic systems.

## Contribution

It introduces a novel mechanical implementation of a topologically bound state similar to Majorana states, previously known only in electronic systems.

## Key findings

- Successfully created a topologically protected bound state in a mechanical system.
- Demonstrated robustness of the state against local perturbations.
- Extended topological protection concepts to bosonic, mechanical systems.

## Abstract

The discovery of topologically non-trivial electronic systems has opened a new age in condensed matter research. From topological insulators to topological superconductors and Weyl semimetals, it is now understood that some of the most remarkable and robust phases in electronic systems (e.g., Quantum Hall or Anomalous Quantum Hall) are the result of topological protection. These powerful ideas have recently begun to be explored also in bosonic systems. Topologically protected acoustic, mechanical, and optical edge states have been demonstrated in a number of systems that recreate the requisite topological conditions. Such states that propagate without backscattering could find important applications in communications and energy technologies. In this work we demonstrate the mechanical analogue of a topologically bound state, a different class of non-propagating protected state that cannot be destroyed by local perturbations. These are well known in electronic systems, such as Majorana bound states in topological superconductors, but remain largely unexplored in a bosonic setting. We implement topological binding by creating a Kekul\'e distortion vortex on a two-dimensional mechanical honeycomb superlattice.