The Kondo effect is one of the most important in quantum physics, describing the strange interference that magnetic atoms can have in metals.

Usually, as metals cool, they become better at conducting electricity, because the reduction in energy means electrons can flow more smoothly. Add in a magnetic atom or two, though, and below a certain temperature (the Kondo temperature), electrical resistance starts to rise again.

That’s the Kondo effect, and we already know a lot about it. But in a physics first, researchers from the California Institute of Technology (Caltech) and Yale University in the US have managed to precisely quantify the effect in a real material via fundamental physics calculations.