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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.
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