Sometimes, there is an absolute limit on the number of terms an officeholder can serve, while, in other cases, the restrictions are merely on the number of consecutive terms.
For example, Maxwell's Equations would always be capitalized, while quantum mechanics is usually un-capitalized. I searched half a dozen sites for an answer to this but found no clue about a rule. So go either way that makes you happy, but (most of all) be consistent.
Interesting when you said No to the first question, because that definition Quantum Physics as the study of Physics in sub-atomic scale is what is written in the Portuguese (I am from Brazil) article of Quantum Physics on Wikipedia. So the Portuguese portion of Wikipedia is wrong about Quantum Physics.