QFS2016 Book of Abstracts

Abstracts

O3.11 Search for New States of Superfluid 3 He in Nanoscale Pores and Silica Aerogel Zimmerman, A.M., Nguyen, M.D., Halperin, W.P. Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA Recent theoretical work on the phase diagram of superfluid 3 He confined in long pores of 200nm diameter has predicted a vastly altered phase diagram, with the possibility of stabilizing the polar phase as well as a number of A-like and B-like phases.1 In order to investigate this experimentally, we have obtained 50% porosity samples of anodic alumina with 200nm co-aligned pores with lengths of 100 µ m. We report the results of NMR measurements of the phase diagram of superfluid 3 He in these samples. This work was supported by the National Science Foundation, DMR-1103625. [1 . ] J. J. Wiman et al., Phys. Rev. B 92, 144515 (2015) O3.12 Linear theory of orbital glass states of 3 He-A in aerogel Fomin Igor P.L. Kapitza Institute for Physical Problems, Russian Academy of Science, Kosygina 2, 119334 Moscow, Russia Spacial variation of the orbital part of the order parameter of 3 He-A in aerogel is represented as a random walk of the unit vector l in a field of random anisotropy produced by the strands of aerogel. For a range of distances, where variation of l is small in comparison with its absolute value, correlation function of directions of l(r) is expressed in terms of the correlation function of the random anisotropy field. With simplifying assumptions about this correlation function a spatial dependence of the average variation l 2 is found analytically for isotropic aerogel and for different types of its anisotropy. Average projections of l on the axes of anisotropy are presented. Numerical estimations of characteristic length of disruption of the long-range order and of the critical anisotropy for restoration of this order are made and compared with experiment and with previous estimations.

84