a) My current research interests are mainly related to strongly correlated electron theories (N-body problem) and the connection of these theories with novel exotic properties of new materials (high temperature superconductivity, colossal magneto-resistance, quantum hall effect ...), e.g. I am studying a peculiar family of compounds, the copper oxides (cuprates, high temperature superconductors) using numerical techniques at zero temperature (Variational Monte Carlo) and at finite temperature (Dynamical mean-field theory). I worked recently at combining the realistic band characterization (Density functional theories) of cuprates with Dynamical mean-field theory, and I could recently put forward the importance of orbital currents for cuprates (C.Weber et al., PRL 102, 017005) and a theory to explain the striking differences between hole and electron doped cuprates (C.Weber et al., Nature Physics, 10.1038/nphys1706).

b) I am also interested in the physics of quantum and classical magnetic frustration in new materials. In particular, I studied how quantum magnetism is affected by topological frustration induced by the geometry of the compound (triangular geometry) and how magnetism is destroyed by chemical substitution (so-called doping) and how it leads to high temperature superconductivity. This theory is important to describe superconductivity in new compounds such as Cobaltates (C.Weber et al., PRB 73, 014519). I also studied by numerical techniques (Monte Carlo simulations) a simple model of classical spins (Heisenberg model, J1-J2 theory) and the effect of frustration and thermal fluctuations in such theories, which leads to many exotic phenomena, such as order by disorder and finite temperature phase transition due to hidden order (C.Weber et al. PRL 91, 177202). This theory is important and relevant for recently studied compounds such as the iron Pnictides.