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Abstracts
I2.1
Non-isothermal Physico-Chemical Processes in Superfluid Helium
Haley R. P.
Lancaster University
Coherent condensates appear as emergent phenomena in many systems, sharing
the characteristic feature of an energy gap separating the lowest excitations from
the condensate ground state. An object moving with high enough velocity that
the excitation spectrum becomes gapless can create excitations at no energy
cost and initiate the breakdown of the condensate. This limit is the well-known
Landau velocity. For the neutral Fermionic superfluid
3
He-B in the T=0 limit,
flow around an oscillating body displays a very clear critical velocity for the
onset of dissipation. However, to our considerable surprise, we have found that
for uniform linear motion there is no discontinuity whatsoever in the dissipation
as the Landau critical velocity is passed and exceeded.
I2.2
Visualizing Textural Domain Walls in Superfluid
3
He by Magnetic
Resonance Imaging
Kasai Jun(1), Okamoto Yohei(1), Nishioka Keishi(1),Takagi Takeo(2), and Sasaki
Yutaka(1,3)
1) Dept. of Physics, Kyoto University, Kyoto, JAPAN.
2) Dept. of Applied Physics, Univ. of Fukui, Fukui, JAPAN.
3) LTM Center, Kyoto University, Kyoto, JAPAN.
A real space image of textural domain walls inside a single 100 micrometer
thickness slab of superfluid
3
He-A was MRI-imaged. Straight lines, which
appeared in between large domains of uniform textures, were textural domain
walls (solitons) with particularly important feature. The observed NMR properties
suggest that the domain wall has almost dipole-locked soliton structure inside
the wall, which connects two regions of uniform
d
=
l
texture with different
chirality, namely
d
,
l
and –
d
,
−
l
. This soliton is accompanied with two surface
chiral domain walls located back to back on both side of the slab surface. The
surface chiral domain walls anchor the dipole-locked soliton in its place.
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