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Abstracts
P1.6
Superfluid transitions of
4
He films under new dimensional and
topological conditions of nanopores
N. Wada(1), T. Matsushita(1), M. Hieda(2)
1)Department of Physics, Nagoya University, Nagoya 464-8602, Japan
2)Col. of Lib. Arts & Sci., Tokyo Medical and Dental Univ., 2-8-30 Kounodai,
Ichikawa, 272-0827, Japan
We have investigated various new superfluid(SF) transitions of the
4
He films
formed in nanopores which have respective conditions of dimension and topology.
The
4
He nanotubes formed in straight nanochannels show SF onset characteristic
to 1D, due to thermal excitations of the 2
π
-phase windings. In 3D nanopore,
even thin film shows a typical 3D SF transition, where the thermal wavelength is
large compared to the period of 3D pore connection. For a thick film in the 3D
pore, we observed a successive phase change from normal to the 2D degenerate
state followed by the 3D SF transition, in a marginal 2-to-3 dimension where the
wavelength is obviously shorter than the 3D period.
P1.7
Highly mobile metastable state of He solid layer on graphite: A glass
formation by mechanical perturbation?
Tomoki Minoguchi
Institute of physics, University of Tokyo
Solid layers of helium on graphite surface is known to undergo a highly mobile
state (HMS) once the solid layer is enforced to slip on the substrate. The HMS
collapses to the original inert state with the life time extending over 10
4
sec.
In this paper, we suggest that the HMS is a structural glass by showing the
similarities between the present system and BEDT-TTF. The latter was recently
uncovered to be an electronic glass if the cooling rate is rapid enough across the
freezing temperature (Wigner crystal formation temperature). We then suggest
that a novel behavior on the metastability of glass should be seen for He-4 case
as the condensation fraction grows in the liquid overlayer.
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