Prof. John Chalker (Theoretical Physics, Oxford University)
"Classical loop models and quantum phase transitions"
I will give an overview of recent work on the statistical physics of lattice models of close-packed loops. The models have two phases -- one in which all loops are finite, and another in which some loops are extended -- and the interest is in universal features of these phases and the transitions between them. The models describe a number of problems in classical statistical physics -- where, for example, the loops may be vortex lines in a three-dimensional random field -- and also many-body quantum systems -- where the loops are world-lines of particles.