Bell-type inequality tests and quantum entanglement from $Lambda$-hyperon spin correlations at high energy colliders


Abstract in English

Spin correlations of $Lambda$-hyperons, extracted from their self-analyzing weak decays, provide unique insight into Bell-type locality tests within the QCD strings formed in high-energy collider experiments. We show from very general considerations that the Clauser-Horne-Shimony-Holt inequality test is typically less stringent for the states produced in QCD strings; however they provide a benchmark for quantum-to-classical transitions induced by varying i) the associated hadron multiplicity, ii) the spin of nucleons, iii) the separation in rapidity between pairs, and iv) the kinematic regimes accessed. These studies also enable the extraction of quantitative measures of quantum entanglement. We explore such questions within a simple model of a QCD string comprised of singlets of two partial distinguishable fermion flavors and compare analytical results to those obtained on quantum hardware. We further discuss a class of spin Hamiltonians that model the complex quantum dynamics of $Lambda$ spin correlations embedded in the QCD string . Prospects for extracting quantum information from $Lambda$ measurements at current and future colliders are outlined.

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