  Reservoir computing (RC) has been considered as one of the key computational
principles beyond von-Neumann computing. Magnetic skyrmions, topological
particle-like spin textures in magnetic films are particularly promising for
implementing RC, since they respond strongly nonlinear to external stimuli and
feature inherent multiscale dynamics. However, despite several theoretical
proposals that exist for skyrmion reservoir computing, experimental
realizations have been elusive until now. Here, we propose and experimentally
demonstrate a conceptually new approach to skyrmion RC that leverages the
thermally activated diffusive motion of skyrmions. By confining the
electrically gated and thermal skyrmion motion, we find that already a single
skyrmion in a confined geometry suffices to realize non-linearly separable
functions, which we demonstrate for the XOR gate along with all other Boolean
logic gate operations. Besides this universality, the reservoir computing
concept ensures low training costs and ultra-low power operation with current
densities orders of magnitude smaller than those used in existing spintronic
reservoir computing demonstrations. Our proposed concept can be readily
extended by linking multiple confined geometries and/or by including more
skyrmions in the reservoir, suggesting high potential for scalable and
low-energy reservoir computing.
