Possible basis for anti-grav
http://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146
Yes, I know it's about temperature. Scroll down a bit to this part:
"Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity"
http://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146
Yes, I know it's about temperature. Scroll down a bit to this part:
"Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity"