Collective behavior in a granular jet: Emergence of a liquid with zero surface-tension

TL;DR

This study demonstrates that a granular jet can mimic a liquid with zero surface tension, exhibiting sheet and cone formations similar to water, and reveals how particle number affects collective behavior and disintegration.

Contribution

It introduces a granular analog to liquid surface tension phenomena, linking granular dynamics to quark-gluon plasma behavior in high-energy physics.

Findings

Granular jets form sheet and cone shapes resembling liquids with zero surface tension.

Reducing particles in the jet causes broadening and disintegration of these shapes.

The experiment parallels behaviors observed in quark-gluon plasma in particle physics.

Abstract

We perform the analog to the "water bell" experiment using non-cohesive granular material. When a jet of granular material, many particles wide, rebounds from a fixed cylindrical target, it deforms into a sharply-defined sheet or cone with a shape that mimics a liquid with zero surface tension. The particulate nature of granular material becomes apparent when the number of particles in the cross-section of the jet is decreased and the emerging sheets and cones broaden and gradually disintegrate into a broad spray. This experiment has its counterpart in the behavior of the quark-gluon plasma generated by collisions of gold ions at the Relativistic Heavy Ion Collider. There a high density of inter-particle collisions gives rise to collective behavior that has also been described as a liquid.