Hydrodynamic damping in trapped Bose gases

T. Nikuni; A. Griffin

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arXiv · cond-mat/9711036

Hydrodynamic damping in trapped Bose gases

T. Nikuni·A. Griffin

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Abstract

Griffin, Wu and Stringari have derived the hydrodynamic equations of a trapped dilute Bose gas above the Bose-Einstein transition temperature. We give the extension which includes hydrodynamic damping, following the classic work of Uehling and Uhlenbeck based on the Chapman-Enskog procedure. Our final result is a closed equation for the velocity fluctuations $δv$ which includes the hydrodynamic damping due to the shear viscosity $η$ and the thermal conductivity $κ$. Following Kavoulakis, Pethick and Smith, we introduce a spatial cutoff in our linearized equations when the density is so low that the hydrodynamic description breaks down. Explicit expressions are given for $η$ and $κ$, which are position-dependent through dependence on the local fugacity when one includes the effect of quantum degeneracy of the trapped gas. We also discuss a trapped Bose-condensed gas, generalizing the work of Zaremba, Griffin and Nikuni to include hydrodynamic damping due to the (non-condensate) normal fluid.

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T. Nikuni, A. Griffin. 1998-01-06. Hydrodynamic damping in trapped Bose gases. https://arxiv.org/abs/cond-mat/9711036

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