MÖBIUS Strip as the Configuration Space for the Case of Two Magnons in Bethe Ansatz

A finite Heisenberg magnetic ring with an arbitrary single-node spin and two spin deviations from the ferromagnetic saturation is considered as the system of two Bethe pseudoparticles. The set of all relevant magnetic configurations spans a surface which can be recognised as a Möbius strip. The dynamics of the system imposes the double twist of all regular orbits of the translation symmetry group.