QCD at small x and Heisenberg spin chains

We give a short review on the application of perturbative QCD to the description of the Regge asymptotics of hadronic scattering amplitude. Considering as an example the small x behaviour of the structure functions of deep inelastic scattering in the generalized leading logarithmic approximation, we show that the Regge asymptotics are governed in perturbative QCD by the contribution of the color-single compound states of reggeized gluons. The interaction between Reggeons is described by the effective Hamiltonian which in the multi-color limit turns out to be identical to the Hamiltonian of the completely integrable one-dimensional 30 Heisenberg magnet of noncompact spin s = 0. We discuss the possibility to find the spectrum of the Reggeon compound states within the Bethe Ansatz approach. (author)