Observation of ​Phase Controllable Majorana​-like Bound States in Metamaterial-based Kitaev Chain Analogues

Motivated by the recent theoretical studies on a quasi-one-dimensional Su-Schrieffer-Heeger ladder model Hamiltonian [1], we experimentally demonstrate that the Majorana​-like Bound States (MBSs) can occur at the open edges of quasi-one-dimensional mechanical metamaterials, analogous to the Majorana Zero Modes at the edges of the Kitaev chain. Specifically, using mechanical systems made of magnetically coupled spinners, we demonstrate (1) the topological phase transition ​signaled by the emergence of the mid-gap MBSs, (2) the localization of MBS ​characterized by decay and oscillation (3) the hybridization of MBSs and ​control of relative phases of wave-function analogues by frequency tuning, and (4) the oscillation of the MBS hybridization splitting with varying the length of the ladder systems. ​We find strong agreement between experiments and theory. The implications to the Kitaev chain, qubits, and braidings, and the possibility of topologically protected mechanical memory are also discussed.