by Prof. G. Mussardo
Abstract: Thanks to integrable quantum field theories, there has been in recent year new understanding on a large number of models
of interest in statistical mechanics or in condensed matter physics, e.g. Ising model in a magnetic field or Sine-Gordon model. Integrability has permitted to determine,
for instance, the exact spectrum of many systems, the explicit determination of the correlation functions of their order
parameters, as well as their thermodynamical properties. In
the seminar there will be discussed two methods which permits to extend this analysis also to non-integrable models: the first one is based on the Form Factor Perturbation Theory while the
second is based on semi-classical techniques. Both approches will
be then illustrated by studying in details the non-integrable features of a particular significant example, the Double Sine-Gordon model.
This model is important in many physical contexts, as in the discussion of quantum spin chains or in the analysis of the O(3) sigma model with topological term.
For More Information: Iwen Jensen tel. 8344-5214 email I.Jensen@ms.unimelb.edu.au