****Technical Abstract**** This project will investigate the effects of pair-breaking scattering by spatially extended objects in p-wave superfluid 3He. Specifically, the extended anisotropic pair-breaking objects are high porosity aerogel immersed in bulk liquid and the boundaries present in a thin film. The physical properties of these systems are strongly influenced by the localized quasiparticle bound states induced by the pair-breaking scattering. The ultimate goal of the proposed experiment is to identify the structure of the impurity states and novel quantum phases predicted to emerge in these systems. Especially, the study of thin films will employ a novel technique involving MEMS devices developed in the PI's group. Merging state-of-the-art MEMS technology to fundamental research could open a pathway to new discoveries and better understanding. The proposed research will be conducted by two teams of graduate and undergraduate students. The PhD students will be trained to gain a wide range of expertise in low temperature physics, nano-fabrication technique, device technology, and computer simulations. Undergraduate students will have hands-on experience in modern scientific research and importantly will have an opportunity to closely observe the entire process of conducting research from planning to publication.
The proposed research addresses a fundamental question: "How does the nature of a quantum matter evolve in response to the presence of disorder or boundaries?" This is an overarching issue because disorder is ubiquitous. Unlike other physical systems, liquid helium three at low temperatures offers an ideal platform for this mainly owing to the fact that it is arguably the cleanest system which we have a detailed quantitative understanding. Furthermore, the superfluid phases of helium three, which can be characterized as more general unconventional superconductor, are known to exhibit extreme sensitivity to external disorder. This project will investigate the effects of controlled disorder on this unique quantum state of matter presented in two distinct forms of disorder: anisotropic disorder in high porosity aerogel and surface disorder in thin films. In this research, a novel experimental technique involving micrometer-scale machines, called MEMS devices, will be employed to investigate the fundamental nature. The ultimate goal of the proposed experiment is to identify disorder induced new quantum phases expected to emerge in these systems. The proposed research will be carried by two PhD students in close collaboration with undergraduate students. Undergraduate research is an important element of education and also a very effective way of retaining Physics undergraduate student in this field.
