16th April 2004 - 09:04 PM
Research groups in the US and Austria say that they have found the best
evidence to date for superfluidity - the flow of a fluid without
resistance - in a Fermi gas made of ultracold lithium-6 atoms. The
results could help physicists understand more about other exotic systems
in nature, such as high-temperature superconductors, neutron stars and
the quark-gluon plasma.
27th August 2004 - 02:52 AM
Extract from the above post publication
"The Duke team says its experiment provides the most direct ever evidence for superfluidity. Earlier this year, a group at Boulder in the US created a Bose-Einstein condensate from a strongly interacting Fermi gas and studied the pairs of fermions that formed. “That was a good experiment, but it doesn’t establish superfluidity,” said Thomas in a press release. “To have superfluidity you’ve got to observe something like hydrodynamics, like we observed.”
Thomas admits that the work could be criticised because it does not demonstrate a well-defined transition at the point where the gas becomes a superfluid. In contrast, the experiment performed by Rudolf Grimm and colleagues at the University of Innsbruck shows an abrupt change - in the collective excitation frequency - at this crossover point (M Bartenstein et al. 2004 arXiv.org/abs/cond-mat/0403716). The transition is also accompanied by oscillations that last a long time."
The super fluidity problem here is that the particles are bunching together and being held in a psuedo bosonic state from which they can not flow. Even assuming they can get through the matrix now that youve doubled their size. This is not the case for bosonic particles which have greater freedom because they are naturally in this state and free to move
Your experiment is holding them in a psuedo bosonic state you have to let them go.
4th October 2008 - 01:50 PM