Thorsten Schmitt operates one of the world-wide most advanced soft X-ray RIXS facilities at the ADRESS beamline of the Swiss Light Source (SLS). His scientific research focuses on correlated-electron materials associated with phenomena such as superconductivity, metal-insulator transitions (MITs), charge order, magnetic order and low-dimensional magnetism. Thorsten Schmitt has developed momentum resolved soft X-ray RIXS at the SLS as a sensitive probe of the spin, charge, lattice and orbital dynamics in copper and iron based superconductors, quasi one-dimensional (1D) cuprate materials as well as in nickelates, vanadates, ruthenates and iridates. In particular, he has discovered a novel Spin-Orbital Separation mechanism in the 1D antiferromagnetic Heisenberg spin-1/2 chain Sr2CuO3 with RIXS at the Cu L3 edge and demonstrated that four-spinon excitations can be accessed directly in a region of phase space clearly separated from the two-spinon continuum using RIXS at the O K-edge. He has applied RIXS to reveal the electronic configuration of NdNiO3 as Ni 3d8 with holes in the O 2p band identifying the bond-disproportionation mechanism as the decisive driver for the MIT in rare-earth nickelates. In recent efforts on time resolved RIXS he was demonstrating the great potential of RIXS spectroscopy to study the ultrafast orbital dynamics and magnetic fluctuations in strongly correlated materials.