Figure 2
Ising spin chains in a T-geometry. A fermionic T-junction suitable for Majorana braiding15 has a spin representation of this structure14, which is described by the Hamiltonian in eq. (19). The couplings between three Ising spin chains are mediated by the components of an additional spin S0, cf. ref.9 and eqs (4, 5). The system can be manipulated by tuning transverse fields (not depicted here) that act on the individual spins σα(j) of the three chains.
