Dynamics of vortex-antivortex pairs and rarefaction pulses in liquid light

Abstract

We present a numerical study of the cubic-quintic nonlinear Schrödinger equation in two transverse dimensions, relevant for the propagation of light in certain exotic media. A well-known feature of the model is the existence of flat-top bright solitons of fixed intensity, whose dynamics resembles the physics of a liquid. They support traveling wave solutions, consisting of rarefaction pulses and vortex-antivortex pairs. In this work, we demonstrate how the vortex-antivortex pairs can be generated in bright soliton collisions displaying destructive interference followed by a snake instability. We then discuss the collisional dynamics of the dark excitations for different initial conditions. We describe a number of distinct phenomena including vortex exchange modes, quasielastic flyby scattering, solitonlike crossing, fully inelastic collisions, and rarefaction pulse merging.

Annihilation and recurrence of vortex-antivortex pairs in two-component Bose-Einstein condensates

“…This recurrence accompanies the creation of rarefaction pulses, which are dark blobs without vorticity [36][37][38]. Jones and Roberts studied the 2D Gross-Pitaevski equation with axisymmetric disturbances, and found that the dispersion relation shows a continuous sequence of a vortex pair and a rarefaction pulse [36].…”

“…In general, a vortex can be nucleated from a low-density region, e.g., owing to a repulsive potential [39,40] or to the outskirt of the trapped condensate [41]. Even in a uniform system, a rarefaction pulse triggers a low-density region, from which a vortex pair appears in a one-component system under some strong disturbance [37,38]. In two-component BECs, the intercomponent interaction enables the continuous transformation between a vortex pair and a rarefaction pulse; a similar phenomenon is observed numerically in threedimensional two-component BECs [33].…”

Oblique collisions and catching-up phenomena of vortex dipoles in a uniform Bose–Einstein condensate

“…While in a uniform superfluid the VD propagates with a constant velocity, in an inhomogeneous system it has complicated trajectory [22,[43][44][45] or even remains stationary [16,43]. The vortex-antivortex annihilation has also been discussed in [46][47][48][49][50][51]. Many important works have been performed on the collisional dynamics of VDs in BECs [20,52,53].…”