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arXiv · 2408.04876

Entanglement Witness for Indistinguishable Electrons using Solid-State Spectroscopy

Tongtong Liu·Luogen Xu·Jiarui Liu·Yao Wang
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Abstract

Characterizing entanglement in quantum materials is crucial for advancing next-generation quantum technologies. Despite recent strides in witnessing entanglement in magnetic materials with distinguishable spin modes, quantifying entanglement in systems formed by indistinguishable electrons remains a formidable challenge. To solve this problem, we introduce a method to extract various four-fermion correlations by analyzing the nonlinearity in resonant inelastic x-ray scattering spectra. These correlations constitute the primary components of the cumulant two-particle reduced density matrix. We further derive bounds for its eigenvalues and demonstrate the linear scaling with fermionic entanglement depth, providing a reliable witness for entanglement. Using the material-relevant strongly correlated models as examples, we show how this entanglement witness can efficiently quantify multipartite entanglement across different phase regions, highlighting its advantage over quantum Fisher information.

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Tongtong Liu, Luogen Xu, Jiarui Liu, Yao Wang. 2025-03-25. Entanglement Witness for Indistinguishable Electrons using Solid-State Spectroscopy. https://doi.org/10.1103/physrevx.15.011056

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