# Fields, Strings and Dualities

In the past half century, quantum field theory has been the fundamental paradigm of theoretical particle physics. Despite enormous progress, important open problems remain, e.g. regarding its non-perturbative behavior. Understanding strongly-coupled models is one of the big challenges of contemporary theoretical physics. Strongly-coupled physics is ubiquitous, arising both in the formal study of general QFT, e.g. at the interacting conformal fixed points of RG flows, and in the Standard Model of particle physics. While numerical modeling is often well-adapted to strongly interacting systems, their analytic study is much more difficult. The large-charge expansion is an approach that allows the analytic study of strongly-coupled systems. Working in sectors of large charge leads to important simplifications in many models at strong coupling, allowing the analytic computation of various observables. Our group is interested in developments in formal theoretical physics.

Currently, our focus is the study of QFTs in sectors of large global charge.

Further research interests include:

- deformed supersymmetric gauge theories and their relations to integrable models from brane constructions
- integrable deformations and their realizations from string theory
- dualities of supersymmetric gauge theories and their brane realizations
- global properties of supersymmetric gauge theories via brane realizations

We have a weekly Fields and Strings seminar.

See also http://www.reffert.itp.unibe.ch