Observation of Second Sound in a Quantum Gas

Second sound is a quantum mechanical phenomenon, which has been observed only in superfluid helium. 

Physicists from the University of Innsbruck, Austria, in collaboration with colleagues from the University of Trento, Italy, have now proven the propagation of such a temperature wave in a quantum gas. 

The scientists have published their historic findings in the journal Nature.

 

The cigar-shaped particle cloud is locally heated with a power-modulated laser beam (green). (Credit: IQOQI/Ritsch)

Credit: http://www.alphagalileo.org