Beyond the absolute

Physicists at the Ludwig-Maximilians University Munich and the Max Planck Institute of Quantum Optics in Garching, Germany, have created an atomic gas in the laboratory that apparently displays a negative value on the Kelvin temperature scale - its temperature is below absolute zero, in other words. A negative absolute temperature, while seemingly impossible by definition, has several absurd consequences such as atoms attracting each other without condensing and so displayed a negative pressure. The claim would also imply that a heat engine with greater than 100% efficiency might be possible.