What Happens Beyond "Absolute Hot"?

Can temperature drop below absolute zero? What happens then? Does it pop out at the other end of the thermometer like Pac-Man and become infinitely hot? Well, kind of, and the seemingly wacky concept is actually surprisingly common in physics.A recent paper published in Physical Review Letters describes a system where negative temperature is used to explain a weird but real phenomenon in our physical world. Scientists describe a physical system that is both below "absolute zero" and above "absol...