- Accepted Paper
Spin entanglement signatures of proton from a light-front Hamiltonian
Phys. Rev. D - Accepted 11 September, 2026
DOI: https://doi.org/10.1103/29wm-ycwp
Phys. Rev. D - Accepted 11 September, 2026
DOI: https://doi.org/10.1103/29wm-ycwp
Quantum entanglement provides a quantitative probe of the internal structure of hadrons and offers a sensitive means to study the quantum correlation in the hadron wave functions. For baryons, the spin state of the three valence quarks forms a tripartite qubit system, whose entanglement structure can be characterized by the four classes of three-qubit states. In this work, we compare the proton spin entanglement obtained from Basis Light-Front Quantization (BLFQ) with that from a quark-diquark model. By analyzing both bipartite and tripartite entanglement, we find that the quark-diquark model yields a substantially more entangled spin state than the BLFQ wave function in the valence Fock sector. This difference mainly originates from the larger W-type and Bell-type entanglement in the quark-diquark model. Within BLFQ, a larger coupling constant and smaller quark mass drive the spin correlation among the valence quarks towards an effective quark-diquark configuration with an active quark and a correlated pair.
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