Chladni solitons and the onset of the snaking instability for dark solitons in confined superfluids

TL;DR

This paper predicts complex solitary wave structures called Chladni solitons in confined superfluids, analyzes their stability, and suggests they could be observed experimentally in ultra-cold gases.

Contribution

It introduces a new family of solutions called Chladni solitons, extending known dark solitons with intersecting vortex lines and analyzing their bifurcation and stability.

Findings

Chladni solitons include cross, spoke wheel, and Greek Phi shapes.

Bifurcation points indicate the onset of snaking instability modes.

Predictions are confirmed by numerical calculations across BEC and BCS regimes.

Abstract

Complex solitary waves composed of intersecting vortex lines are predicted in a channeled superfluid. Their shapes in a cylindrical trap include a cross, spoke wheels, and Greek $\Phi$, and trace the nodal lines of unstable vibration modes of a planar dark soliton in analogy to Chladni's figures of membrane vibrations. The stationary solitary waves extend a family of solutions that include the previously known solitonic vortex and vortex rings. Their bifurcation points from the dark soliton indicating the onset of new unstable modes of the snaking instability are predicted from scale separation for Bose-Einstein condensates (BECs) and superfluid Fermi gases across the BEC--BCS crossover, and confirmed by full numerical calculations. Chladni solitons could be observed in ultra-cold gas experiments by seeded decay of dark solitons.