Prof. Alexey Rubtsov did his Master and Ph.D. in the group of Prof. L.V. Keldysh at Moscow State University. The topic of his Ph.D. was a theory of nonlinear optics of surfaces and nanostructures. After the Ph.D. defense, Prof. Rubtsov expertise in the theory of condensed matter, and in particular correlations. He started with theory of phase transitions, and when migrated to the theory and numerical simulations of correlated electrons. Hi proposed a land-slighting Continuous Time Quantum Monte Carlo algorithm, as well a new kind of diagram technique for correlated systems based on so called dual variables. These works contributed to his habilitation thesis. Last years, Prof. Rubtsov started working of emulations of quantum information devices.