Vortices Play Leapfrog in Liquid Light ⚡ экспресс
The experimental observation of vortex leapfrogging in a two-dimensional fluid of light is reported. By injecting two vortex-antivortex pairs and using time-resolved phase-sensitive imaging, dynamics precisely described by the point-vortex model with an external radial flow were recorded. Precise control over the initial vortex spacing revealed configurations where leapfrogging breaks down, identifying two dissipation mechanisms. The first stems from phase slips at high initial speeds. The second occurs when injection of multi-charged vortices generates a dispersive shock wave that becomes a persistent source of phase defects. These findings deepen the understanding of vortex dynamics and dissipation in superfluid systems.
Superfluid helium flows without friction, and vortices are born within it—microscopic funnels, much like whirlpools in water. Two such vortices can play leapfrog: one jumps over the other, and they hop in a circle. This game was predicted by Richard Feynman back in the 1950s. Only now has it been directly observed.
Now physicists have staged leapfrog in "liquid light"—a medium where light behaves like a superfluid. They created vortices with a laser and tracked their motion with an ultrafast camera. When the vortices were sped up too much, a sharp jolt occurred—a shock wave. The game broke down: the vortices collided and vanished, releasing heat. That’s the only way such a perfect fluid can lose energy. Capturing the moment was possible thanks to ultra-high-speed filming.
This discovery helps understand how motion decays in superfluid media and could lead to ultra-precise rotation sensors.
🎯 Feynman predicted vortex leapfrog while pondering the mysteries of turbulence, and it's only now been physically seen—in laser light.
🎬 Liquid light is almost like a lightsaber from science fiction, where energy becomes tangible.