“Quantum-based material’s calculations are a simulation activity, not a theoretical activity.”

The theoretical activity is the search of the “optimal theory”: the simplest mathematical description that covers all the empirical facts observed to-day in this particular field of science. For solid state physics, that “optimal theory” is already known, as quantum mechanics based on the Schrödinger equation. The usage of the well-known theory for the calculation of the properties of the model (not for developing a new theory, more global or more local than the initial one) is known as the simulation activity — such as the quantum-based material’s calculations

Many people intuitively have the opposite opinion because they define theory as a usage of the formulae: both the derivation of new equations (a theoretical activity) and the calculation of the parameters (a simulation activity). Maybe my guess is incorrect as I am not familiar with this problem and the views of these people