Superfluid Topics

• critical velocity
• moses chan
• sound velocity
• fluid density
• penn state university
• supersolid
• superfluids
• speed reduction
• high pressures
• vestergaard
• refractive index
• absolute value
• slow speed
• speed of light
• dutton
• zachary
• helium
• lambda
• research group

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Superfluid, Superfluid

In this model, the sound velocity is the "critical velocity" above which superfluidity is destroyed.

At the so-called Lambda temperature, where the normal fluid density equals the total density, the is no longer superfluid.

Lene Vestergaard Hau, S. E. Harris, Zachary Dutton, Cyrus H. BehrooziLight speed reduction to 17 metres per second in an ultracold atomic gasNature 397, 594-598 (18 February 1999) This does not change the absolute value of c , nor is it completely new: any medium other than vacuum, such as water or glass, also slows down the propagation of light to c / n where n is the material's refractive index. The very slow speed of light and high refractive index observed in this particular experiment, moreover, is not a general property of all superfluids.

When helium-4 is cooled below about 200 mK under high pressures, a fraction (~1%) of the solid appears to become superfluid. Moses Chan's Research Group. " Supersolid ." Penn State University, 2004.

Source: Wikipedia > Superfluid