Penn State Science
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Electrons in Confined Geometry
Supersolid
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At temperatures below 2.176K, liquid He-4 enters into a superfluid state and flows without any friction. The onset of superfluidity is associated with Bose-Einstein condensation, where the He-4 atoms (bosons) condense into a single momentum state and acquire quantum mechanical coherence over macroscopic scales. Counter to intuition, superfluid-like behavior is even possible in solid helium. Torsional oscillator measurements of Eunseong Kim and Moses Chan in 2004 found evidence of superflow of solid helium confined in porous Vycor glass with pore diameter of 7 nm. Since this time "Supersolidity" of He-4 has been demonstrated within porous gold (490 nm) and also in the bulk phase. Chan's group is currently investigating the effects of disorder, or lack there of, on the supersolid phase transition.

Publications

2004 · 2005 · 2006 · All
E. Kim and M. H. W. Chan, "Supersolid Helium at High Pressure," Phys. Rev. Lett. 97, 115302 (2006)
E. Kim and M. H. W. Chan, "Observation of Non-Classical Rotational Inertia in Solid 4He Confined in Porous Gold," J. Low Temp. Phys. 138, 859 – 864 (2005)
A. Clark and M. H. W. Chan, "Specific Heat of Solid Helium," J. Low Temp. Phys. 138, 853 – 858 (2005)
E. Kim and M. H. W. Chan, "Observation of Superflow in Solid Helium," Science 305, 1941 – 1944 (2004)
Disclaimer
M. H. W. Chan : Supersolid helium