Witnessing Spin-Orbital Entanglement using Resonant Inelastic X-Ray Scattering

Abstract:Entanglement plays a central role in quantum technologies, yet its characterization and control in materials remain challenging. Recent developments in spectrum-based entanglement witnesses have enabled new strategies for quantifying many-body entanglement in macroscopic materials. Here, we develop a protocol for detecting spin-orbital entanglement using experiment-accessible resonant inelastic x-ray scattering (RIXS). Central to our approach is the construction of a Hermitian generator from experimentally measurable spectra, which allows us to compute the quantum Fisher information (QFI) available in spin--orbital systems. The resulting QFI provides upper bounds for $k$-producible states and thus serves as a robust witness of spin-orbital entanglement. To account for realistic experimental limitations, we further extend our framework to include relaxed QFI bounds applicable to measurements lacking full polarization resolution.

Quantum Physics (quant-ph); Strongly Correlated Electrons (cond-mat.str-el)

arXiv:2512.06718 [quant-ph]

(or arXiv:2512.06718v2 [quant-ph] for this version)

https://doi.org/10.48550/arXiv.2512.06718 Focus to learn more arXiv-issued DOI via DataCite

https://doi.org/10.1103/nyxb-nqtq Focus to learn more DOI(s) linking to related resources

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