# A classic formula for pi has been discovered hidden in hydrogen atoms

For the first time, scientists have discovered a classic formula for pi in the world of quantum physics. Pi is the ratio between a circle’s circumference and its diameter, and is incredibly important in pure mathematics, but now scientists have also found it “lurking” in the world of physics, when using quantum mechanics to compare the energy levels of a hydrogen atom.

Why is that exciting? Well, it reveals an incredibly special and previously unknown connection between quantum physics and maths.

*“I find it fascinating that a purely mathematical formula from the 17th century characterises a physical system that was discovered 300 years later,”* said one of the lead researchers, Tamar Friedmann, a mathematician at the University of Rochester in the US. Seriously, wow.

http://www.sciencealert.com/a-classic-formula-for-pi-has-been-discovered-hidden-in-hydrogen-atoms