QFS2016 Book of Abstracts

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)

110