****Technical Abstract**** Nuclear magnetic resonance (NMR) techniques will be used to explore the dynamics of quantum solids and fluids in systems where striking new phenomena have been observed at low temperatures. These systems include solid 4He in the range of 0.1 to 0.5 K for which a large unexpected quantum plasticity has been reported, and clusters of atoms (3He, HD, H2) confined to the interior of nanostructures for which enhanced quantum effects occur in the restricted geometries. The latter are predicted to exhibit new thermodynamic features because the confining dimension is less that the De Broglie wavelengths and the energy states will be fully quantized. In both cases new high sensitivity solid state NMR techniques will developed to study the microscopic dynamics of these systems non-invasively. The studies will determine the effect of quantum plasticity on the tunneling of 3He impurities in solid 4He, and the nature of the quantization of nanoclusters of atoms trapped in nanoporous materials that hold promise for improved capabilities of hydrogen storage. The project will support the training of a PhD student in the design and application of NMR techniques for observing signals from very low densities of atoms and molecules in extreme conditions. These techniques will be important for a number of applications in industry such as geological exploration and for investigating defects in structural materials.
The fundamental microscopic motion of atoms and molecules is governed by the laws of quantum mechanics, and while the general principles of quantum mechanics has been verified in many laboratory experiments, the behavior of simple atoms in extreme conditions of density and temperature has not been fully explored for the simplest materials, such as the weakly interacting quantum fluids and solids comprised of light atoms and molecules such as helium and hydrogen. The dynamics of the constituent atoms is determined by the wave functions describing the atoms and in its most simple terms the wave functions of the atoms overlap and as a result the atoms can exchange places. As a result of this unique quantum mechanical aspect atoms can tunnel through a lattice structure independent of temperature. This tunneling motion will be exploited to probe the microscopic dynamics of solid helium for which large anomalies have been observed in the elastic properties of very pure crystals at low temperatures. The project will use magnetic resonance techniques to carry out non-invasive measurements of the atomic motions in these quantum solids using approaches similar to but not identical to those used in magnetic resonance imaging in medical applications. Students and collaborators working on the project will design new magnetic resonance techniques needed for the experiments and the applications of the new technologies will be of interest to applications in industry such as geological exploration and investigation of structural materials.
