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New Phase of 3 He? Jeevak M. Parpia, Cornell University, DMR 1202991 Disorder introduced via Aerogel – an extremely dilute glass – disturbs pairing of 3 He. Aerogel, when properly grown, should be highly homogenous. Theoretical results point to anisotropy as the means to promote the chiral A phase over the B phase. We demonstrated that an ESP (Equal Spin Paired) phase is introduced between the B phase and the normal phase (compare blue diamonds to red boxes in the upper figure). However, the superfluid fraction is inconsistent with the angular momentum aligned along the compression direction. Instead, an oriented polar phase with a line of nodes around the equator is the likely alternate explanation. The dissipation (shown at right) would be larger in the Polar (ESP) than the B phase, while the superfluid fraction would be reduced from that in the B phase.
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Modification of Phase Diagram by Confinement Jeevak M. Parpia, Cornell University, DMR 1202991 Using a microfabricated cavity formed by joining silicon to glass (see figure D), the superfluidity of confined 3 He was investigated. We found that the A phase (confined to the high pressure high temperature corner of the bulk phase diagram (C)), now appears at low pressure in both diffuse (A) and specular (B) versions of the phase diagram. (specularity is induced by covering surfaces with 4 He superfluid). A small coexistence region with both A&B phase signatures is seen in the NMR frequency shift (Figs E,F below right). This coexistence is likely due to small in homogeneities in the cell. The cell bows slightly under pressure (see G – where we plot the distribution in %/nm vs cell height D http://www.sciencemag.org/content/340/61 34/841.full.html D F E G
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Broader Impacts Jeevak M. Parpia, Cornell University, DMR 1202991 1. Organized Symposium at March Meeting Baltimore MD 2013. 2. Panelist and Presenter at Conferences for Undergraduate Women in Physics (CUWiP) at Cornell, January 2013. 3. Supervising Undergraduate research student Bryce Kobrin at Cornell (work on resonant characteristics of quartz forks). 4. Supervised Patrick Yu (2012) (see figure at left) Patrick worked on making composite Graphene- Silicon Nitride resonators. 5. International advisory board for QFS 2013 (Matsue- Japan) and QFS 2015 (Buffalo NY). 6. Suggested 2 invited symposia for 2014 March meeting. Patrick Yu: High school student – currently at Caltech, worked with us to fabricate Graphene-Silicon Nitride resonators at the CNF. Here shown examining a mask that he fabricated.
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