A quantum is the smallest amount of energy there is. So when you hear someone say such and such a thing was or is a “quantum leap,” he or she is actually talking about the smallest possible leap of any kind found in nature. It’s an ironic use of the phrase. However, I’ll grant you that the quantum leap represents an enormous step in thought. In a quantum leap, a particle is either here, or it’s there – in an instant. This discovery changed the world.