Speaker
Description
Quantum turbulence (QT) - the quantum analogue of classical fluid turbulence - emerges from the complex dynamics of quantized vortices in Bose-Einstein condensates (BECs). In this talk, I will present our recent numerical investigations on vortex nucleation and the onset of QT in two distinct BEC systems driven by fundamentally different mechanisms.
First, I will discuss a quasi-2D dipolar BEC (168Er) stirred by a circularly moving Gaussian obstacle, where we observe the nucleation of vortex dipoles and clusters depending on the stirring frequency and dipole-dipole interaction strength. Second, I will present results on a two-component immiscible BEC (85Rb-87Rb) where we merge the two condensates using external forces applied either perpendicular or parallel to the interface, as well as through an immiscible-to-miscible quenching transition. The merging process generates vortices via Rayleigh-Taylor and Kelvin-Helmholtz-like dynamics, which subsequently develop into quantum turbulence. In both systems, we analyze the compressible and incompressible kinetic energy spectra through the Madelung transformation. Despite the different drive mechanisms, both systems exhibit the universal Kolmogorov k−5/3 scaling in the incompressible kinetic energy spectrum, accompanied by a k−3 enstrophy cascade in the ultraviolet regime - the hallmark of quantum turbulence.