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Abstracts
P3.30
Intrinsic precession of the spin of Bogoliubov-quasiparticles at the
inhomogeneously-distorted B-phase of the superfluid
3
He.
Evgeny Surovtsev
Kapitza Institute for Physical Problems, Russia
Bogoliubov-Nambu Hamiltonian has two energy levels separated by the gap.
The levels are two-fold degenerate due to the spin. Adiabatic change of
quasiparticle position at k-space produces non-Abelian gauge potential, which
is a generalization of Berry-connection for the case of degenerate levels. For
the distorted B-phase Berry-connection is found. We assume that the adiabatic
force is produced by inhomogenuity of the order parameter. Resulting effective
magnetic field acting on the spin degree of freedom is directed perpendicular to
the quasiparticle momentum and the force. The influence of intrinsic precession
of quasiparticles possibly can be observed at NMR experiments as a reduction of
a signal from the regions with large enough gradients.
P3.31
Observation of a new superfluid phase for
3
He embedded in
“nematically ordered” aerogel
Zhelev, N.(1), Reichl, M.(1), Abhilash, T.S.(1), Smith, E.N.(1), Nguyen, K.X.(2),
Mueller E.J.(1) and Parpia, J.M.(1)*
(1)Laboratory of Atomic & Solid State Physics, Cornell University, Ithaca, NY
14853, USA
(2)School of Applied and Engineering Physics, Cornell University, Ithaca, NY
14853, USA
Theory predicts that nanoscale confinement and anisotropic disorder profoundly
change the stability of the pairing in superfluid
3
He, and can lead to novel phases.
A torsion pendulum is used to study
3
He confined in an extremely anisotropic,
nematically ordered aerogel with
≈
10 nm thick alumina strands, spaced
≈
100
nm apart aligned with the pendulum axis. A measurement of the pendulum’s
period yields the fraction of the fluid that is decoupled from the container and
is related to the superfluid fraction. We observe kinks when superfluid fraction
is plotted versus temperature, corresponding to phase transitions at various
pressures. We find a new superfluid phase that is not seen in bulk
3
He. Drawing
on theoretical work we argue that at low pressure, this new phase is the Polar
Phase.
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