Enhancement and sign change of magnetic correlations in a driven quantum many-body system

Periodic driving can be used to coherently control the properties of a many-body state and to realize new phases which are not accessible in static systems. In this context, cold fermions in optical lattices provide a highly tunable platform to investigate driven many-body systems and additionally offer the prospect of quantitative comparisons to theoretical predictions. We implement a driven Fermi-Hubbard model by periodically modulating a 3D hexagonal lattice. Driving the system near-resonantly to the interaction enables us to independently control the single particle tunneling and the magnetic exchange energy. As a consequence, we are able to show that anti-ferromagnetic correlations in a fermionic many-body system can be enhanced or even switched to ferromagnetic correlations. Furthermore, a detailed study of the dynamics of double occupancies in the driven many-body system gives insights into thermalization, adiabatic preparation and heating.