title: Supersolidity.
abstract: The observation of nonclassical rotational inertia (NCRI) by the torsional oscillator in 2004 gave rise to a renaissance in the study of solid helium-4. Recent theoretical and experimental studies found evidence that disorder in the solid plays a key role in enabling superfluidity. A recent experiment found a marked increase in the shear modulus that shares the same temperature and helium-3 impurity concentration dependence as that of NCRI. This correlation indicates that the onset of superfluidity requires the pinning and stiffening of the dislocation network by helium-3.
authors.affiliation: Department of Physics, Pennsylvania State University, University Park, PA 16802, USA. chan@phys.psu.edu
authors.forename: M H W
authors.initials: MH
authors.lastname: Chan