Optically-Induced Faraday-Goldstone Waves

TL;DR

This paper demonstrates that ultrafast optical pulses can induce long-lived Faraday-Goldstone waves in quantum solids, revealing a new way to create and control dynamic, periodic structures in quantum materials.

Contribution

It introduces a theoretical framework for optically generating and observing Faraday-Goldstone waves, a novel phenomenon in ordered quantum solids, with experimental validation on K$_{0.3}$MnO$_{3}$.

Findings

Observation of long-lived Faraday-Goldstone waves in quantum solids.

Prediction of Higgs-Goldstone beating and coherent energy exchange.

Robustness of the light-induced state against thermal noise.

Abstract

Faraday waves, typically observed in driven fluids, result from the confluence of nonlinearity and parametric amplification. Here we show that optical pulses can generate analogous phenomena that persist much longer than the pump time-scales in ordered quantum solids. We present a theory of ultrafast light-matter interactions within a symmetry-broken state; dynamical nonlinear coupling between the Higgs (amplitude) and the Goldstone (phase) modes drives an emergent phason texture that oscillates in space and in time: Faraday-Goldstone waves. Calculated signatures of this spatiotemporal order compare well with measurements on K$_{0.3}$MnO$_{3}$; Higgs-Goldstone beating, associated with coherent energy exchange between these two modes, is also predicted. We show this light-generated crystalline state is robust to thermal noise, even when the original Goldstone mode is not. Our results offer a new pathway for the design of periodic structures in quantum materials with ultrafast light pulses.