The Many Faces of Quantum Fields

Quantum Field Theory (QFT) is the main framework of all fundamental physical theories up to the Planck scale. It not only generates the Feynman diagrams that match scattering experiments in particle physics to a high precision. In the past decades QFT has found many applications from condensed matter physics and quantum optics to cosmology covering an enormous range of scales. The connection between different regimes requires concepts like symmetry breaking and renormalization. In a parallel development, perturbative calculation schemes have been supplemented by approaches to the nonperturbative regime. On the analytic side these are for instance mean field theory, large-N approximations and instanton methods. The latter are closely related to other solitonic excitations like monopoles, vortices and strings which allowthe study of non-vacuum sectors of the theory. Chiral fermions, present for topological reasons, and supersymmetry have brought in new phenomena including the concept of duality. The discretisation on space-time lattices is the best suited regulator of QFT with respect to numerical computations. In particular lattice gauge theory has developed many techniques to explore the world of strong interactions. Moreover, field theories at finite temperature and density and in gravitational backgrounds have become prominenttools for the investigation of physical systems. These include phase transitions in the early universe with effects like cosmic strings and baryogenesis which under some circumstances call for QFT methods out of equilibrium. With such a broad range of applications, often developed in a specific context, exchange of expertise and crossfertilization between different branches of QFT is highly important and useful. The present workshop aims at bringing together experts in various aspects of QFT to discuss their work and share their ideas. The program of the workshop is planned to have plenary sessions reviewing recent developments in the field,and also to leave room for discussion and interaction in smaller groups.