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Abstracts
O4.5
Experiments on Topological Defects in a Dirac Superfluid
Autti(1), Etlsov(1), Heikkinen(1), Volovik(1), Zavjalov(1), Yudin(2), Dmitriev(2)
1) Low Temperature Laboratory, Aalto University, Finland
2) P.L. Kapitza Institute for Physical Problems RAS
Topological quantum matter systems support topological objects in the
order-parameter field and exotic quasiparticles with universal properties among
systems of the same class. We study with NMR spectroscopy linear objects
(vortices) in the polar phase of superfluid
3
He, a triplet superfluid with a Dirac
nodal line. The single- and half-quantum vortices are created by rotation, and
spin vortices by NMR excitation. All types of vortices can be also created by
the Kibble-Zurek mechanism. We demonstrate the Aharonov-Bohm effect for
spin waves and discuss the role of disorder. In future this Dirac superfluid allows
studies of flat-band fermions and of the fermion condensation in vortex cores.
O4.6
Pressure Dependence of the Phase Diagram of Superfluid
3
He in the
Presence of Anisotropic Disorder
M.D. Nguyen, A.M. Zimmerman, and W.P. Halperin
1) Northwestern University, Department of Physics and Astronomy, Evanston,
IL 60208, USA
In previous work, we have observed dramatic changes in the phase diagram
of superfluid
3
He in the presence of anisotropic quasiparticle scattering from
negatively strained silica aerogel.
1
,
2
We have discovered a B-like superfluid phase
more stable than the A-phase in a magnetic field, marked by a tricritical point and
a strain-dependent critical magnetic field. In addition, a strain-driven textural
transition appears in the B-like phase at low temperatures. Here we report the
pressure dependence of these phenomena from our NMR measurements. This
work was supported by the National Science Foundation, DMR-1103625
[1
.
] JIA Li et al, PRL 112, 115303 (2014)
[2
.
] JIA Li et al, PRL 114, 105302 (2015)
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