Measurement of Bell-type inequalities and quantum entanglement from $Λ$-hyperon spin correlations at high energy colliders

Abstract

Spin correlations of Λ-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 Λ spin correlations embedded in the QCD string . Prospects for extracting quantum information from Λ measurements at current and future colliders are outlined.

Maximally entangled proton and charged hadron multiplicity in Deep Inelastic Scattering

“…Entanglement is a nonlocal correlation unique to quantum systems [1], see also the reviews [2,3]. There are various proposals how to study entanglement in high energy physics such as neutrino oscillations, spin correlations of t − t quarks or hyperons [4][5][6][7]. A measure of entanglement which is of particular interest is entanglement entropy [8].…”

Maximally entangled proton and charged hadron multiplicity in Deep Inelastic Scattering

“…Entanglement is a nonlocal correlation that is unique to quantum systems [1], see also the reviews [2,3]. There are various proposals how to study entanglement in high energy physics such as neutrino oscillations, spin correlations of t − t quarks or Λ hyperons [4][5][6][7]. A measure of entanglement that is of particular interest is entanglement entropy [8].…”

Medium induced jet broadening in a quantum computer

“…Beside field theory based simulations, they have also been applied to specific topics such as nuclear structure [32][33][34][35][36][37], neutrino oscillation [38] and string theory [39]. Concerning collider oriented physics, these technologies have, for example, been used to simulate hard probes like heavy flavors [40] and jets [41,42], optimize parton showers [43][44][45] and jet clustering algorithms [46][47][48] as well as in the detection of quantum anomalies [49] and the study of spin correlations at high energies [50]. Although such applications are still highly constrained by the performance of current quantum computers [51], even the (re)formulation of problems in a language accessible to these machines turns out to be highly non-trivial.…”