Quantum information with top quarks in QCD

Top quarks represent unique high-energy systems since their spin correlations can be measured, thus allowing to study fundamental aspects of quantum mechanics with qubits at colliders. We present here the general framework state a top-antitop ($t\bar{t}$) quark pair produced through chromodynamics (QCD) in collider. argue that, general, total that probed collider is given terms production density matrix, which necessarily gives rise mixed state. compute $t\bar{t}$ from most elementary QCD processes, finding presence entanglement and CHSH violation different regions phase space. show any realistic hadronic statistical mixture these processes. focus on experimentally relevant cases proton-proton proton-antiproton collisions, performed LHC Tevatron, analyzing dependence energy collisions. provide experimental observables for CHSH-violation signatures. At LHC, signatures are by measurement single observable, case represents Cauchy-Schwarz inequality. extend validity tomography protocol proposed literature more states, mechanism. Finally, we measured only weak form Bell's theorem, containing number loopholes.