Spontaneous emergence of a spin state for an emitter in a time-varying medium

TL;DR

This paper demonstrates that time-varying media can induce a spontaneous spin state in embedded emitters, with experiments using bouncing droplets revealing the interplay between source motion and time-reversed waves.

Contribution

It introduces a novel mechanism where time-varying media create a spontaneous spin state in sources, validated through experimental and stability analysis.

Findings

Time-varying media induce emitter spin states.

Experimental validation with bouncing droplets.

Stable spin states enable model calibration.

Abstract

Time varying media can dramatically modify the emission of embedded sources by producing time reversed waves refocusing on the source. Here we show that such a back action can create an angular momentum by setting the source in a spontaneous spin state. We experimentally implement this coupling using self-propelled bouncing droplets sources coupled to the surface waves they emit on a parametrically excited bath. The spin state dynamics result from a self-organized interplay between the source motion and the time reversed waves. The discrete stability analysis agrees with the experimental observations. In addition, we show that these spin states provide a unique opportunity for an experimental access to parameters enabling comparison and calibration of the various existing models.