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 leaps are the sole cause of the emission of electromagnetic radiation, including light, which occurs in the form of quantized units called photons. Ironically, when laymen use the term colloquially, they use it to describe large jumps in progress, when in reality a quantum leap is a very small change of state.