Have you ever heard someone say something similar to “The company made a quantum leap in productivity this past quarter.”, as if trying to say that a lot of progress was made?
I do not know the origin of the phrase “quantum leap”, but you should know that this euphemism, which is especially popular in American business, is essentially a self-negation.
The classic definition of the noun “quantum” is the smallest quantity of radiant energy that can exist independently.
A “quantum” in physics is the energy that is equal to the frequency of the associated radiation times Planck’s constant.
And a “quantum leap” refers to the discontinuous, instantaneous jump of an electron in an atom from one quantum state to another.
So taking a “quantum leap” truly refers to taking the smallest leap possible — not exactly what most Americans mean when they say it.
I suspect that many people misapply the phrase “quantum leap” so that they can sound smarter.
But they end up sounding a bit ignorant or pompous to anyone who has been exposed to even a little bit of modern physics.