Supersolid, a slippery new state of matter

Moses H.W. Chan (Pennsylvania State Univ University Park ) DMR 0706339

100 101 102 103 104 105 106

40

6080

100

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600800

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T1/

2 [m

K]

x3 [ppb]

T1/2, temperature where NCRI is reduced to 50%of its low temperature value in samples of different 3He concentrations, (x3). These data points, obtained with different torsional oscillator cells, were found to follow a curve that describes the condensation of 3He atoms onto the dislocation lines. ( From reference 3.)

The observation of superfluid-like or non classical rotational inertia (NCRI) behavior in solid 4He have been replicated in five other laboratories.1

Evidence of pinning of quantum vortices by 3He impurities and/or dislocation were also found.2

Measurements in solid with different 3He impurities show the onset of NCRI tracks the condensation of 3He atoms onto the dislocation lines,3 consistent with the finding from the University of Alberta of the stiffening of the solid at low temperature.

A specific heat peak correlated with the onset of NCRI was observed.4

1.Science 319, 1207( 2008), Perspective.2 Phys. Rev. B 77, 184513( 2008) 3. Phys. Rev. Lett. 100, 065301(2008). 4. Nature 449, 1025(2007)

The discovery of NCRI has energized the field of quantum solids and spawned more than 180 papers and six dedicated workshops, including two this summer at Les Trellies ( France ) and at the International Center for Theoretical Physics at Trieste.

E. Kim, co-discoverer of the phenomenon was awarded the Lee-Richardson-Osheroff Prize of 2008.

The P.I. is the director of a NSF/RET site grant (DMR-0648837) giving the P.I. and his students ample opportunities to participate in outreach activities to the public.

The P.I. is a member of a NAS Committee studying the effects of current shortage of liquid helium on US research activities.

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Children at the Central Pennsylvania Festival of the Arts found out from Moses Chan, Josh West and Zhigang Cheng that low temperature physics is cool.

Supersolid, a slippery new state of matter Moses H.W. Chan (Pennsylvania State Univ University Park ) DMR 0706339