All That Matters

Usually we tend to think about temperature as being related to the motion of atoms. At lower temperatures, atomic motions slow down. Absolute zero, defined as zero Kelvin or −273.15 degrees Celsius, then is the point where all atomic motion stops. But what comes beyond that, does something like a negative absolute temperature exist? Indeed, as Ulrich Schneider and colleagues from Munich have now demonstrated impressively in this week’s issue of Science, it does. […]