  Transport properties of dense liquid helium under the conditions of planet's
core and cool atmosphere of white dwarfs have been investigated by using the
improved centroid path-integral simulations combined with density functional
theory. The self-diffusion is largely higher and the shear viscosity is notably
lower predicted with the quantum mechanical description of the nuclear motion
compared with the description by Newton equation. The results show that nuclear
quantum effects (NQEs), which depends on the temperature and density of the
matter via the thermal de Broglie wavelength and the ionization of electrons,
are essential for the transport properties of dense liquid helium at certain
astrophysical conditions. The Stokes-Einstein relation between diffusion and
viscosity in strongly coupled regime is also examined to display the influences
of NQEs.
