First observation of bright solitons in bulk superfluid He-4

TL;DR

This paper reports the first experimental observation and theoretical confirmation of bright solitons in bulk superfluid helium-4, revealing their formation, properties, and stability conditions.

Contribution

It provides the first direct experimental evidence and theoretical analysis of bright solitons in bulk superfluid He-4, expanding understanding of nonlinear wave phenomena in quantum fluids.

Findings

Bright solitons form after plasma-induced compression in superfluid He-4.

Solitons exhibit dispersionless propagation and amplitude-velocity relation.

High-amplitude solitons become unstable and form dispersive shock waves.

Abstract

The existence of bright solitons in bulk superfluid He-4 is demonstrated by time-resolved shadowgraph i maging experiments and density functional theory (DFT) calculations. The initial liquid compression that leads to the creation of non-linear waves is produced by rapidly expanding plasma from laser ablation. Af ter the leading dissipative period, these waves transform into bright solitons, which exhibit three chara cteristic features: dispersionless propagation, negligible interaction in two-wave collision, and direct dependence between soliton amplitude and the propagation velocity. The experimental observations are supp orted by DFT calculations, which show rapid evolution of the initially compressed liquid into bright soli tons. At high amplitudes, solitons become unstable and break down into dispersive shock waves.