Tuesday, February 21, 2012

1111.1173 (Enrico Vogt et al.)

Scale invariance and viscosity of a two-dimensional Fermi gas    [PDF]

Enrico Vogt, Michael Feld, Bernd Fröhlich, Daniel Pertot, Marco Koschorreck, Michael Köhl
We investigate the collective excitations of a harmonically trapped
two-dimensional Fermi gas from the collisionless (zero sound) to the
hydrodynamic (first sound) regime. The breathing mode, which is sensitive to
the equation of state, is observed at a frequency two times the dipole mode
frequency for a large range of interaction strengths and temperatures, and the
amplitude of the breathing mode is undamped. This provides evidence for a
dynamical SO(2,1) scaling symmetry of the two-dimensional Fermi gas. Moreover,
we investigate the quadrupole mode to measure the shear viscosity of the
two-dimensional gas and study its temperature dependence.
View original: http://arxiv.org/abs/1111.1173

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