At low temperature, the equation of motion' for the spin density m in nuclear polarized paramagnetic liquids (e.g. , liquid He, HeHe mixtures) and gases (e.g. , He, H i ) differs from the conventional Fick's law form Bm/t)t =D V' m of classical systems. In general, the equation becomes nonlinear and anisotropic and the transverse component has an oscillatory (wave) as well as a diffusive charac...

By the semi-inverse method, a variational principle is obtained for the Thomas– Fermi equation, then the Ritz method is applied to solve an analytical solution, which is a much simpler and more efficient method. 2002 Elsevier Science Inc. All rights reserved.

Sound waves are excited in an optically trapped degenerate Fermi gas of spin-up and spin-down atoms with magnetically tunable interactions. Measurements are made throughout the crossover region, from a weakly interacting Fermi gas through the resonant Fermi superfluid regime to a Bose condensate of dimer molecules. The measured sound velocities test theories of hydrodynamic wave propagation and...

We discuss a recently proposed analytic solution to the Thomas– Fermi (TF) equation and show that earlier approaches provide more accurate results. In particular, we show that a simple and straightforward rational approximation to the TF equation yields the slope at origin with unprecedented accuracy, as well as remarkable values of the TF function and its first derivative for other coordinate ...

Starting from a Lagrangian density of a superfluid Bose-Fermi mixture we derive a coupled set of nonlinear Schrödinger equations for the system. In the absense of interspecies Bose-Fermi interaction the Bose component satisfies a standard Gross-Pitaevskii equation, whereas the Fermi component satisfies a Ginzburg-Landau-type equation suitable for the Fermi superfluid. To study dynamics we use t...

We calculate the oscillation frequencies of trapped Fermi condensate with particular emphasis on the equation of state of the interacting Fermi system. We confirm Stringari's finding that the frequencies are independent of the interaction in the unitary limit, and we extend the theory away from that limit, where the interaction does affect the frequencies of the compressional modes only.