Optical Signatures of Quantum Skyrmions

Magnets have recently emerged as promising candidates for quantum computing, particularly using topologically-protected nanoscale spin textures. While the quantum dynamics of such spin textures has been theoretically studied, direct experimental evidence of their nonclassical behavior remains an open challenge. To address this, we propose to employ Brillouin light scattering (BLS) as a method to probe the quantum nature of skyrmions in frustrated magnets. We show that, for a specific geometry, classical skyrmions produce symmetric sidebands in the BLS spectrum, whereas quantum skyrmions exhibit a distinct asymmetry arising from vacuum fluctuations of their rotation. By studying the photon-skyrmion interaction, we calculate the BLS spectrum using a quantum master equation and show that sideband asymmetry serves as a robust witness of energy level quantization. We find that this asymmetry is pronounced at low temperatures, and can be controlled by input laser power. These findings establish a concrete protocol for the optical detection of nonclassical features in spin textures, paving the way for exploring their role in quantum applications.