Bethe Ansatz for XXX chain with negative spin

XXX spin chain with spin s = -1 appears as an effective theory of Quantum Chromo-dynamics. It is equivalent to lattice nonlinear Schroediger's equation: interacting chain of harmonic oscillators [bosonic]. In thermodynamic limit each energy level is a scattering state of several elementary excitations [lipatons]. Lipaton is a fermion: it can be represented as a topological excitation [soliton] of original [bosonic] degrees of freedom, described by the group Z(2). We also provide the CFT description (including local quenches) and Yang-Yang thermodynamics of the model.