[dragonwriter]

> > In theory a computer should be able to model any physical process

> Wait, which theory is that?

The Church-Turing-Deutsch Principle. (Which isn’t a theory in the empirical sense, but somewhat more speculative.)

> Or are we suggesting that you can build a computer out of whatever physical process you want to model?

Well, you obviously can do that. Whether that computer is Turing equivalent, more limited, or potentially a hypercomputer is...well, Church-Turing-Deutsch says the last is always false, but good luck proving it.