Programme

Speaker: Stepehen J. Summers
Title: Modular Structure and the Construction of Quantum Field Models
Abstract: Algebraic quantum field theory has begun to contribute ideas to one of the most difficult and important problems in mathematical quantum field theory --- the construction of models. I shall report on some of these ideas. One approach makes an intriguing use of an intrinsic modular localization to construct nets of observable algebras from the initial data of a positive energy representation of the Poincare group without direct appeal to quantum fields. Another development has been motivated by integrable quantum field models with factorizable scattering matrix in two space-time dimensions. In this approach, relatively easily constructible models of nonlocal quantum fields are used to obtain local observable algebras by purely algebraic means, avoiding the necessity of directly constructing the local quantum fields, which are significantly more complicated objects than the initial nonlocal fields. In all these approaches Tomita-Takesaki modular theory is essential.