Michael Köhl

Understanding strongly correlated quantum many-body systems remains a challenge both for experiment and theory. In particular, the interplay of interactions, kinetic energy, and dimensionality is complex and governs the occurrence and properties of low-temperature quantum phases. A paradigmatic example of a strongly correlated many-body problem is that of interacting spin-1/2 fermions on a periodic lattice. Depending on the Hamiltonian parameters, different quantum phases are realized. For example, for weak interactions and low filling of the lattice, the fermions delocalize into Bloch waves and constitute a metallic state with finite charge compressibility. In contrast, for strong repulsive interactions at half filling the fermions form a Mott insulator that occurs when the kinetic energy can no longer overcome the energy gap due to repulsive on-site interactions. In this talk, I will review the latest results from our lab of exploring this physics.