Quantum-based material’s calculations are a simulation activity because they apply previously developed theory instead of trying to develop a new theoretical approach of its own. Instead of deducing new mathematical formalism from experiments, they try to reproduce these experiments in silico.

Intuitively, however, the border is not clear. Sometimes, scientific communities only tell the difference between experimentalists and “theoreticians”, that is, researches who generally use theoretical/computational instead of experimental techniques.