Feynman diagrams are an important tool in modern theoretical physics, with applications in solid-state, high-energy physics, and quantum chemistry. Doc. dr. Denis Golež from the Department of Theoretical Physics and his colleagues from the Flatiron Institute (USA), Berkeley University (USA) and the University of Örebro (Sweden) discovered a new approach for using Feynman diagrams in quantum materials, published in Physical Review X. Higher-order Feynman diagrams are challenging in strongly correlated quantum systems due to their computational complexity. This study uncovered a ‘hidden structure’ within these high-order diagrams based on the separability of quantum propagators, see figure, significantly reducing computational demands. The algorithm was applied to non-perturbative problems where traditional quantum Monte Carlo methods would fail, offering a promising new tool for diagrammatic computations. This theoretical advancement is expected to greatly facilitate the discovery of new quantum collective states, such as excitonic magnetism and spin glasses.