Researchers, for the first time ever, have found a classic formula for pi concealed in the world of quantum physics. Everybody is aware of the word pi. It is the ratio among a circle’s circumference and its diameter, and is very vital in pure mathematics, but now scientists have also discovered it “lurking” in the world of quantum physics, while using quantum mechanics to link the energy levels of a hydrogen atom. So why is that even exciting? Well, it reveals an exceedingly special and previously unknown connection among quantum physics and mathematics. It is quite interesting that a purely mathematical formula from the early 17th century portrays a physical system that was discovered 300 years later.