Atomic gases at negative kinetic temperature.
We show that thermalization of the motion of atoms at negative temperature is possible in an optical lattice, for conditions that are feasible in current experiments. We present a method for reversibly inverting the temperature of a trapped gas. Moreover, a negative-temperature ensemble can be cooled (reducing |T|) by evaporation of the lowest-energy particles. This enables the attainment of the Bose-Einstein condensation phase transition at negative temperature.
Mosk
A P
AP
Department of Science & Technology, University of Twente, AE Enschede, The Netherlands.