Supersolid :-


At temperatures below 2.176K, liquid helium-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, which are bosons, condense into a single momentum state and acquire quantum mechanical coherence over macroscopic scales. Bose-Einstein condensation of alkali atoms in the vapor phase was achieved in 1995 and there is strong evidence for superfluidity in these systems.

†††††††† Perhaps counter to intuition, superfluid-like behavior is thought possible even in solid helium. Torsional oscillator measurements of Eunseong Kim in 2004 indeed found evidence of superflow on solid helium confined in porous Vycor glass with pore diameter of 7 nm [1], in porous gold with pores of 490 nm [2] and also in bulk solid helium [3]. Very recently Tony Clark and Xi Lin also found evidence of superflow in solid molecular hydrogen.

†††††††††††††††††† The work in this project aims at elucidating the fascinating properties of this new stare of matter [4].


[1] E. Kim and M.H.W. Chan, Nature 427, 225 (2004)

[2] E. Kim and M.H.W. Chan, Science 305, 1941(2004)

[3] E. Kim and M.H.W. Chan, J. Low Temp. Phys. 138, 859 (2005)

[4] A. Cho, Science 309, 38( 2005)


Powerpoint presentations :-