# York Schröder: Research

## Quantum Field Theory

Quantum field theory is the language in which all of modern physics is formulated. It represents the marriage of quantum mechanics with special relativity and provides the mathematical framework in which to describe the creation and destruction of hoards of particles as they pop in and out of their ethereal existence and interact. Whether you want to understand the collisions of protons in the next high-energy collider, how teams of electrons co-operate inside solids, or how black holes evaporate, you need to work with quantum field theory. Moreover, it has also proven to be a remarkably subtle and rich subject for mathematicians, providing insights into many new areas of mathematics.

## Elementary Particle Physics

To learn from the flood of new high-precision experimental data that is expected from the LHC over the next decade, focused theoretical effort is needed on the theoretical side, to confront the observed phenomena with precise predictions from the Standard Model. Only such a comparison will enable us to filter tiny new signals out ouf overwhelmingly large - but known - background processes. Among the main building blocks for such high-precision theoretical calculations are higher-order perturbative expansions, which are made possible due to a fascinating interplay between computer-aided symbolic manipulation, insight into underlying mathematical structures and methodological improvements in particle phenomenology.

## Matter under extreme conditions

Many physical properties of a hot and expanding system (as present in heavy ion collisions as well as in cosmology) are encoded in its partition function. In its conceptually simplest form, the partition function is given by the dependence of the system's thermodynamic pressure on temperature as well as other parameters such as the baryo-chemical potential. At very high temperatures, these thermodynamic observables are amenable to weak-coupling techniques, and hence allow - via an effective field theory reformulation - the use of an arsenal of powerful calculational techniques as developed in particle physics.