Bethe ansatz

24/01/2011 | Seminar Talk in Theoretical Physics, Humboldt University of Berlin

The Heisenberg model is a simple quantum mechanical model to describe ferromagnetism. We use an effective Hamiltonian that only contains spin states of adjacent electrons. In 1931, Hans Bethe (Nobel prize 1967) presented an ansatz to analytically solve the Heisenberg model in one dimension (spin chain). The model is interesting because it illustrates how useful the introduction of quasi particles can be and it is one of the best examples for a completely integrable system.