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Abstracts
I1.1
New faces of superfluid
3
He: Higgs bosons, Majorana fermions and
Alice strings
Eltsov Vladimir
Department of Applied Physics, Aalto University, Finland
Topological superfluid
3
He possesses collective modes of the order parameter,
which are analogous to Higgs boson of the Standard Model of particle physics,
and fermionic excitations of Majorana, Weyl or Dirac character, which can live
in bulk or as bound states at interfaces and order-parameter defects. We discuss
new possibilities for studies of those states opened by recent advances in the
experimental techniques. The developments include ultra-sensitive probes based
on Bose-Einstein condensates of magnon quasiparticles and new superfluid phases
engineered with nanostructured confinement. One example is the polar phase,
where a long-time elusive half-quantum vortex has been discovered.
I1.2
Possible quantum-liquid-crystal phases in helium monolayers
adsorbed on graphite
Hiroshi Fukuyama(1,2), S. Nakamura(2), M. Kamada(1), R. Nakamura(1) and
T. Matsui(1)
1) Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku,
Tokyo 113-0033, Japan
2) Cryogenic Research Center, The University of Tokyo, 2-11-16 Yayoi,
Bunkyo-ku, Tokyo 113-0032, Japan
Recently, physics of 2D helium adsorbed on graphite is attracting renewed
interests and developing rapidly in two directions. One is the possible supersolidity
in 2D
4
He and the other the quantum spin liquid (QSL) magnetism in 2D
3
He.
We discuss that both the astonishing phenomena are associated with a new
state of matter, the quantum liquid crystal (QLC), where possibly only the
orientational symmetry is broken. The hypothesis was drawn from our latest heat
capacity measurements on three different systems, i.e.,
4
He/
4
He/gr,
3
He/
3
He/gr
(S. Nakamura et al., arXiv:1406.4388v2) and
3
He/HD/HD/gr. In the last system,
we found that a commensurate solid phase with quite different QSL properties
from those of the already known QSL in the compressible
3
He/
3
He/gr QLC phase
is stabilized essentially at a single density.
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