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Superfluids
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Superfluids

Super-properties

superfluid helium droplet ,
       Peter Taborek, University of California, IrvineSuperfluidity is a quantum property of some liquids and gases that become infinitely fluid below a certain temperature. A superfluid flows without any effort through thin capillaries or even small holes only a few atoms large. If you fill a porous container, porcelain for instance, with superfluid helium, the container will empty itself! Make it rotate in a ring; it will rotate for weeks without slowing down!

Superfluidity is similar to superconductivity: in one case, a liquid flows with no friction; in the other, an electric current flows with no resistance. Superfluids have other surprising properties; for instance, their whirlpools are all identical (they are “quantized”). Because of their amazing thermal conduction, they do not boil: quantum phenomena that are visible to the naked eyes are rare…

This conduction is also what makes superfluid helium essential as a liquid refrigerant for the creation of very intense magnetic fields, at the CERN in Geneva for experiments on elementary particles for instance.

The origin of superfluidity is similar to that of superconductivity and this time, it is the helium-4 atoms that are the bosons which form a condensate.

Researchers even discovered superfluidity where they did not expect it to be: in helium-3 which is composed of fermions,not bosons.

Since then, they wonder whether supersolids could exist, i.e. solid materials that would be superfluid!

 

 

CNRSSociété Française de PhysiqueTriangle de la physique
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CNRSSociété Française de PhysiqueTriangle de la physique