  XXX spin chain with spin $s=-1$ appears as an effective theory of Quantum
Chromodynamics. 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.
