Kinetics of the formation of compact quantum clusters in stochastic conservative systems

Tom Heitmann, John Gaddy, Jagat Lamsal +1 more

Georg Wolschin

An analytical model for the kinetic equilibration of finite Bose systems is outlined. The corresponding transport equation is solved exactly through a nonlinear transformation. The model is applied to the equilibration of a cold quantum gas including implicitly the formation of a Bose-Einstein condensate through particle-number conservation.

Piotr Garbaczewski

Tao Pang

He cluster by removing the attractive tail in the interaction between some of the atoms in the system with the diffusion quantum Monte Carlo simulation. The ground-state energy, kinetic energy, cluster size, and density profile of the cluster are evaluated against the percentage of the atoms without the attractive tail. The condition for the cluster to lose its ability to form a quantum liquid droplet at zero temperature is found and analyzed. The cluster is no longer able to form a quantum liquid droplet when about two-thirds of pairs of attractive interaction are removed. The findings are helpful to the current studies on the formation of quantum liquid droplets from cold atoms.

V. P. Belavkin

P. Comaron, M. Matuszewski, D. Sanvitto +2 more

Vortex clustering is commonly associated with conservative two-dimensional quantum-fluid dynamics. Therefore, particle loss is mainly expected to limit clustering by shortening the time available for vortex correlations to develop. Here we show instead that particle loss can enhance transient vortex clustering beyond the conservative evolution. We numerically study freely decaying, confined two-dimensional condensates initialized with random distributions of vortices and antivortices, and find a pronounced nonmonotonic dependence of the maximum clustering on particle lifetime. The enhancement is strongest at intermediate particle-loss rates, where loss-induced background rarefaction and incompressible kinetic energy relaxation occur on comparable timescales. Our results identify a finite dynamical window, selected by linear particle loss, in which a confined compressible quantum fluid develops stronger same-sign vortex correlations than in the conservative limit.