Superfluidity is a phenomenon in which quantum-mechanical behavior is manifested on a macroscopic level. With recent advancements in the experimental techniques and increase in the computational power,systems exhibiting superfluidity have emerged as a fertile ground to explore the non-equilibrium physics questions, in general, and the phenomenon of turbulence, in particular.
In this talk, I will focus on two-dimensional superfluidsand present our recent results on the interaction of the particles with the superfluid field at zero temperature.
Particles of low velocity, traveling without dissipation in a superfluid, can interact and emit sound when they collide. We propose a minimal model in which the equations of motion of the particles, including a short-range repulsive force, are self-consistently coupled with the Gross-Pitaevskii equation. We show that this model generates naturally an effective superfluid-mediated attractive interaction between the particles ; and we study numerically the collisional dynamics of particles as a function of their incident kinetic energy and the length scale of the repulsive force. We find a transition from almost elastic to completely inelastic (sticking) collisions as the parameters are tuned. We find that aggregation and clustering result from this sticking transition in multiparticle systems.
Also, to include an example of a three-dimensional system, I will discuss our recent results on the intermittency of the finite-temperature superfluids.