1975 R. P. Poplavskii publishes "Thermodynamical models of information processing" (in Russian)[1] which showed the computational infeasibility of simulating quantum systems on classical computers, due to the superposition principle. 1976 Polish mathematical physicist Roman Stanisław Ingarden publishes a seminal paper entitled "Quantum Information Theory" in Reports on Mathematical Physics, vol. 10, 43–72, 1976.