Fig. 1

Proposal for generating a twisted magnon beam exploiting the Aharanov–Casher effect. Incident spin waves (impinging from left) that propagate in a cylindrical magnetic insulator waveguide traverse a region with a linear charge density λ_e (marked yellow). As demonstrated here, a magnonic twisted beam emerges to the right and can be quantified by the topological charge \(\ell \propto \lambda _{\mathrm{e}}\), which is associated with a monopole-like vector potential, \({\mathbf{A}}_{\mathrm{e}}({\mathbf{r}})\sim \frac{{\lambda _{\mathrm{e}}}}{r}\widehat {\mathbf{e}}_\phi\) that is intimately related to the Dirac phase for magnons