Pressure and stress tensor expressions in the fluid mechanical formulation of the Bose condensate equations

Abstract

It is shown that a momentum equation identical in form to that of the familiar Navier-Stokes fluid, can be derived for the fluid condensate of a weakly interacting Bose gas. For the condensate the pressure is given by the simple barotropic relation p= rho ²/4, while the anisotropic stress tensor sigma _ij' depends only on the density and density of gradients.