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.
quantum theory. A theory in physics based on the principle that matter and energy behave both as particles and as waves. According to this theory, matter and energy are composed of tiny units of electromagnetic energy called quanta.. a theory for predicting the discrete energy states of atoms and of radiation. 2. any theory that describes a force or field using the methods of quantum mechanics: a quantum theory of gravitation.