We develop and apply advanced computational methods to understand, predict and design the fundamental properties of materials at different length scales. These include first-principles 
methods such as density-functional theory (DFT) and its time-dependent extension (TDDFT), wavefunction-based complete active space configuration interaction (CASCI), and Green’s function based many-body quantum-field-theory approaches like the GW approximation and the Bethe-Salpeter equation.