Mathematical Physics

Topological and Dirac materials are large classes of recently discovered materials with many unique proprieties that have received immense amount of attention, including the Nobel Prizes in Physics in 2010 and 2016. We study many different phenomena in topological and Dirac materials, using methods spanning from effective low-energy models to full ab-initio calculations.

Superconductivity is the astonishing physical phenomenon of a material conducting electrical current without any resistance, i.e. without any ohmic losses. Ever since its discovery more than 100 years ago, superconductivity has fascinated scientists, who have attempted to develop suitable theories. To increase the understanding of novel forms of superconductivity, we develop theoretical methods and selfconsistent calculations.

Quantum information is a cross-disciplinary field with great potential impact on future information technology. Key applications in the field are information processing, secure communication, simulations of quantum systems, and metrology. We use geometric and topological techniques to develop new forms of robust logical gates for quantum computation and to seek a deeper understanding of non-classical correlations, in particular quantum entanglement and Bell-type non-locality.

Physical phenomena occur in general under non-equilibrium conditions, because of time-dependence, influence from external force fields, and local variations in the environment. Measurements intrinsically invoke disturbances which give rise to fluctuations that may or may not be desired. Our task is to develop new theoretical framework for studies of dynamical aspects of correlated materials and apply it to address properties of concrete systems.

Ultrafast dynamics in magnetic materials has recently emerged as an intriguing area of modern science. In this field, ultrashort radiation pulses are used to excite a material to a non-equilibrium state that may lead to ultrafast demagnetization, magnetization reversal or even generation of magnetization. The underlying fundamental mechanisms are however poorly understood. To unveil these we develop analytical models and ab initio theory to advance the understanding of ultrafast magnetic processes.