TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.14.2.025
TI  - Interplay of Kelvin-Helmholtz and superradiant instabilities of an array of quantized vortices in a two-dimensional Bose-Einstein condensate
PY  - 2023/02/28
UR  - https://www.scipost.org/SciPostPhys.14.2.025
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 14
IS  - 2
SP  - 025
A1  - Giacomelli, Luca
AU  - Carusotto, Iacopo
AB  - We investigate the various physical mechanisms that underlie the dynamical instability of a quantized vortex array at the interface between two counter-propagating superflows in a two-dimensional Bose–Einstein condensate. Instabilities of markedly different nature are found to dominate in different flow velocity regimes. For moderate velocities where the two flows are subsonic, the vortex lattice displays a quantized version of the hydrodynamic Kelvin–Helmholtz instability (KHI), with the vortices rolling up and co-rotating. For supersonic flow velocities, the oscillation involved in the KHI can resonantly couple to acoustic excitations propagating away in the bulk fluid on both sides. This makes the KHI rate to be effectively suppressed and other mechanisms to dominate: For finite and relatively small systems along the transverse direction, the instability involves a repeated superradiant scattering of sound waves off the vortex lattice; for transversally unbound systems, a radiative instability dominates, leading to the simultaneous growth of a localized wave along the vortex lattice and of acoustic excitations propagating away in the bulk. Finally, for slow velocities, where the KHI rate is intrinsically slow, another instability associated to the rigid lateral displacement of the vortex lattice due to the vicinity of the system's boundary is found to dominate.
ER  -

@Article{10.21468/SciPostPhys.14.2.025,
	title={{Interplay of Kelvin-Helmholtz and superradiant instabilities of an array of quantized vortices in a two-dimensional Bose-Einstein condensate}},
	author={Luca Giacomelli and Iacopo Carusotto},
	journal={SciPost Phys.},
	volume={14},
	pages={025},
	year={2023},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.14.2.025},
	url={https://scipost.org/10.21468/SciPostPhys.14.2.025},
}