Temperature is typically thought of as the average energy of individual atoms or molecules within a given collection. For atoms of similar mass, this "kinetic temperature" would basically be their ...

Absolute zero is often thought to be the coldest temperature possible. But now researchers show they can achieve even lower temperatures for a strange realm of "negative temperatures." Oddly, another ...

A cloud of atoms with a temperature beyond absolute zero – which is also bizarrely hotter than any positive temperature imaginable – could be a mysterious new quantum state of matter. Luca Donini at ...

Energy distribution of atoms in a thermal state. For positive absolute temperatures (upper part, blue), the low energy states have the highest population; for negative absolute temperatures, the high ...