Abstract: The basic laws governing atoms and electrons are well understood, but it is impossible to make predictions about the behaviour of large systems of condensed matter. A common approach is to introduce simple models and to use notions of statistical mechanics. I will review certain quantum spin systems such as the Heisenberg model. As it turns out, they can be represented by models of random permutations and of random loops.

Coffee will be served at 12:00 before the lecture
at Schreiber building 006