QFS2016 Book of Abstracts

Abstracts

P3.26 Search for spatially-modulated phases in confined superfluid 3 He Lev V. Levitin(1), Nikolay Zhelev(2,3), Robert G. Bennett(2,4), Jeevak M. Parpia(2), Andrew J. Casey(1), John Saunders(1) 1) Department of Physics, Royal Holloway, University of London, UK 2) Department of Physics, Cornell University, USA Superfluidity in 3 He arises via p-wave pairing, and the rich order parameter structure allows for multiple superfluid phases. It is predicted that confinement to a slab of thickness of order 10 coherence lengths will, near the A-B transition, trigger the spontaneous appearance of domain walls between regions of superfluid B phase with different orientation, creating a spatially-modulated (striped) phase. Our NMR measurements on a 1.1 um slab of 3 He at low pressure disagree both with the NMR signatures of single-domain B phase, and a periodic stripe phase. However they can be explained by a spatially-modulated phase with domain structure supporting unequal amounts of different domains. P3.27 Suppression of Tc and gap of superfluid 3 He by confinement in a 200 nm slab geometry Heikkinen Petri(1), Casey Andrew(1), Levitin Lev(1), Parpia Jeevak(2), Rojas Xavier(1), Zhelev Nikolay(2), Saunders John(1) 1) Royal Holloway, University of London, Department of Physics, UK 2) Cornell University, Department of Physics, USA The order parameter of superfluid helium-3 confined in a cavity with height comparable to the coherence length is dominated by surface pair-breaking. We describe an accurate determination of the suppression of the superfluid transition temperature, Tc, in an engineered nanofluidic 200 nm slab at various pressures. The results are compared to the predictions of quasi-classical theory. We start from a solid 3 He film on the surfaces, and then tune the surface pair-breaking by pre-plating them with a solid 4 He film and eventually with a superfluid 4 He film. Small volumes of bulk 3 He at opposite ends of the cavity mark the unsuppressed Tc and rule out discrepancies due to temperature gradients. 3) Now at Corning Incorporated, USA 4) Now at Vantage Power Ltd, UK

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