Quantum Condensed Phases
Our most recent result was to understand what happens when an obstacle is moved through a real condensate, including the layer separating it from the outside. There the critical speed we had computed before in the homogeneous case fall to zero, so that one cannot use anymore a criterion based upon a transition from elliptic to hyperbolic flow equations. We have shown that, thanks to a rescaling of the equations in the boundary layer, there is no critical speed, but only a smooth transition from a wave drag to a more classical vortex shedding problem. I plan in the near future to incorporate in this picture the effects of the quantum fluctuations to represent what I have called the quantum braking.
Another issue still under investigation is the occurrence of finite time singularities in the momentum distribution due to the absence of smooth momentum distribution at equilibrium.
