''How to go below zero temperatures.''
http://www.newscientist.com/article...-create-temperatures-below-absolute-zero.html
''And the experiment which achieved that!''
http://www.newscientist.com/article/dn23042
http://www.newscientist.com/article...-create-temperatures-below-absolute-zero.html
''And the experiment which achieved that!''
http://www.newscientist.com/article/dn23042