Effects of Confinement on Quantum Fluids

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This is an experimental condensed matter physics project that seeks to understand the effect of confining liquid helium into one and two dimensions. It has been shown that on a hydrogen surface, the inert layer, or the minimum helium coverage for the appearance of superfluidity in the T=0 limit, is half a liquid monolayer. This raises the question of whether the inert layer can be reduced further on an even weaker substrate, such as an alkali metal surface. A recent calculation predicted that on a cesium-silver compound surface, a dilute hydrogen layer will not solidify and will exhibit superfluid behavior. It has been found recently that helium-3 and other gases are easily adsorbed into the interior of single-wall-carbon-nanotubes. If helium remains liquids at low temperatures, as is predicted, this will be an experimental realization of one dimensional Luttinger liquid. Torsional oscillator, heat capacity and pulsed NMR techniques will be employed to study these confined quantum systems.%%%This is an experimental condensed matter physics project that seeks to understand the consequences of confining liquid helium in one and two dimensions. Liquid helium is an unique liquid in that its properties are dominated by quantum mechanics at low temperatures and transforms into a superfluid. The physics of the superfluid state is analogous to the superconducting state of certain metals and alloys. By adsorbing atomically thin helium films onto solid surfaces an into the interior channels of recently discovered single-all-carbon nanotubes, the properties of superfluidity in two and one dimensions can be explored with highly sensitive mass decoupling and other techniques. In addition to addressing a number of fundamental questions of quantum systems in reduced dimensions, these experiments will also shed insights on the physics of high temperature superconductors and on artificially engineered nanoscale structures. Students associated with this project will receive excellent training, with state-of-the-art instrumentation, that will prepare them for careers in academia or industry.