# Research groups at ITP

Picture of the ITP professors at the 100th anniversary of the institute, 10th-11th June 2022

Front row (seated from left to right) Annette Zippelius and Georg Christoph Lichtenberg.

Back row (standing from left to right) Laura Covi, Peter Sollich, Stefan Klumpp, Matthias Krüger,
Karl-Henning Rehren, Fabian Heidrich-Meisner, Reiner Kree, Steffen Schumann, Marcus Müller,
Stefan Kehrein

Prof. Laura Covi, PhD: Particle Cosmology

Prof. Dr. Steffen Schumann: Collider Phenomenology

Prof. Dr. Karl-Henning Rehren: Fundamentals of Quantum Field Theory

Our research targets at an improved understanding and theoretical description of the fundamental interactions in nature, the resulting dynamics of elementary particles, and corresponding phenomena at high and low energy scales. Our interests range from mathematical physics, to particle collider phenomenology, and cosmology. The common ground of our research activities is the application of Quantum Field Theory.

The group of Laura Covi works on the interplay of particle physics and cosmology developing extensions of the Standard Model of particle physics to take into account cosmological components like Dark Matter or cosmological epochs like inflation and studying mechanisms for the production of Dark Matter and the Baryon asymmetry in the Universe via analytical and numerical methods.

The group of Karl-Henning Rehren studies axiomatic approaches to QFT to consolidate its mathematical foundations, and perturbative approaches to improve the construction of specific models.

The group of Steffen Schumann is specialised on the particle-physics phenomenology at high-energy colliders. The focus is on the development of analytical and numerical methods to predict and interpret the outcome of scattering experiments as they are performed for example at the LHC.

Prof. Dr. Stefan Kehrein

Prof. Dr. Fabian Heidrich-Meisner

apl. Prof. Dr. Salvatore R. Manmana

The Göttingen Condensed Matter Theory groups work on quantum many-body systems that exist in strongly correlated electron materials, mesoscopic systems and quantum simulators. Our current main interest is in the nonequilibrium physics of such systems and we carry out research on both ultrafast dynamics in correlated materials and the statistical physics of closed quantum systems. We combine analytical approaches and state-of-art computational methods and frequently utilize concepts from quantum information theory. Examples of specific research directions include Sachdev-Ye-Kitaev models, thermalization in closed quantum systems, many-body localization, electronic relaxation dynamics after optical excitations, electron-phonon coupled systems, Floquet systems, and topology in condensed matter systems.

Prof. Dr. Matthias Krüger

Prof. Dr. Peter Sollich

In the area of non-equilibrium statistical physics we study systems that exhibit very slow relaxation processes (e.g. glasses, jammed solids), are dominated by strong fluctuations (e.g. complex fluids, reaction networks, phononic friction, radiative heat transfer) or are driven out of equilibrium by internal and external driving (e.g. active and biological matter, rheology). To tackle these challenges we develop theoretical tools based on stochastic field theory and hydrodynamics, path integrals, nonlinear response theory, cavity theory, random matrix theory and projection methods. These are deployed alongside numerical approaches including stochastic simulations, population dynamics and solvers for continuum field theories, to help us understand the fascinating range of emergent collective behaviour that non-equilibrium systems can have.

Prof. Dr. Marcus Müller

Our studies in the area of polymer physics and soft biological matter address the collective behavior and dynamics in diverse systems, ranging e.g. from the rheology of car tire materials, via the self-assembly of copolymers for filtration membranes, to the endo- and exocytosis of synaptic vesicles. Properties of soft materials often rely on universal physical principles like e.g. self-assembly, and there is a rich interplay between thermodynamics, single-molecule dynamics, and collective structure formation or transformation that opens opportunities to direct soft materials into nonequilibrium states by processing. We aim to identify the relevant characteristics, devise particle-based and field-theoretic models that are both, simple and predictive, and study them by large-scale simulation and self-consistent field theory.

Prof. Dr. Annette Zippelius (Staistical Physics)

Prof. Dr. Reiner Kree (Statistical Physics)

Prof. Dr. Kurt Schönhammer (Condensed Matter)

Prof. Dr. Detlev Buchholz (Quantum Field Theory)

Prof. Dr. Gerhard C. Hegerfeldt (Quantum Optics)

Prof. Dr. Hubert Goenner (Gravitation, Theory of Relativity)