![]() While similar configurations in an anisotropic cloud have been considered in the past where the ordering of the linear layout is not destroyed 20, our isotropic system gives rise to clusters with rich dynamics. In particular, we study the clustering dynamics of arrangements of \(N_v\) vortices arranged on a line passing through the centre of the cloud, with a symmetric uniform distribution of vortices on each side. This combination allows us to observe the dynamical formation of the clusters and determine under which initial imprinting conditions such dynamics happen. This layout has a symmetry that is expected to favour the formation of clusters, but also has the characteristic of being geometrically very different from clusters. Our configuration of choice is the case of simple one-dimensional linear structures which are symmetrical about the centre of the cloud. The system under investigation has been chosen with an eye to possible experimental implementations, as vortices can be controllably imprinted on ultracold atomic samples 8, 19. In this work, we numerically study the conditions under which linear vortex structures, imprinted onto a trapped BECs, can evolve into vortex clusters. The combination of these effects is at the core of the formation of vortex clusters, turbulence or vortex lattices.įor what concerns vortex clusters, the many features of trapped BECs are ideal to gain precious insight, both in real experiments and in numerical simulations, on the dynamics of the clusters' formation and the conditions for their existence and stability. ![]() It can lead to a rotational motion where the vortices rotate around each other, or a linear motion where the vortices travel in parallel. This can be seen as a vortex-vortex interaction that depends on the separation of the vortices as well as their topological charges 18. In addition, each vortex creates a velocity field that affects the motion of the other vortices similarly to the way seen in fluid physics. ![]() The gradient of the background density created by the trapping potential induces a precession of the vortex about the center of the trap. In trapped BECs, the vortex dynamics are dictated by density and phase gradients of the superfluid background. Notably, in BECs vortices appear as localised topological defects which carry quantised angular momentum 15, 16, 17. The processes and parameters that lead to the formation of vortex clusters rather than, e.g., turbulence or disorder, are however less understood and investigated.Ītomic BECs are a good platform for the generation and study of vortex clusters and their dynamics due to their extensive controllability in the experiments 11 and the wide availability of tools for numerical simulations both at zero 12 and finite temperature 13, 14. In the optical regime, vortex cluster formations have also been demonstrated in microcavity exciton-polariton condensates 10. Bound structures such as vortex-vortex or vortex-antivortex pairs have been created in BECs 5, 6, 7, 8 and in ultracold Fermi gases 9. The notion of vortices and vorticity is ubiquitous in physics, as it appears in classical physics, e.g., in hydrodynamics, gravitational physics, electromagnetism 1 and non-linear optics 2, as well as in in the quantum realm, through quantum turbulence and quantum hydrodynamics in superfluids 3 and superconductors 4.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |