Observability of a sharp Majorana transition in a few-body model

We propose experimentally observable signatures of topological Majorana quasiparticles in the few-body limit of the interacting cold-atom model of Iemini et al. [F. Iemini, L Mazza, L. Fallani, P. Zoller, R. Fazio, and M. Dalmonte, Phys. Rev. Lett. 118.200404 (2017)]. In this limit, the total on-site density and single-body correlations change smoothly with the model parameters, while the calculated mutual information of opposite ends of the lattice indicates a sharp transition of the system to a topological ground state. Furthermore, local-density and -parity measurements provide an experimentally viable path for observing the ground-state Majorana quasiparticles in ultracold atoms. Our results lay out a promising future for utilizing few-body systems as a testing ground for Majorana physics.