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.
1. quantum-a discrete amount of something that is analogous to the quantities in quantum theory. quantity-the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable.. quantum - (physics) the smallest discrete quantity of some physical property that a system can possess (according to quantum theory). quantity, measure, amount-how much there is or how many there are of something that you can quantify.