The most accurate thermometer in the known universe looks nothing like a thermometer. It is a copper vessel the size of a large cantaloupe, filled with ultrapure argon gas and studded with microphones ...

Over the past 60 years, a considerable number of theories and experiments have claimed the existence of negative absolute temperature in spin systems and ultracold quantum gases. This has led to ...

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 ...