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Entanglement and quantum tomography with top quarks at the LHC

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arxiv 2003.02280 v3 pith:MBGDTINR submitted 2020-03-04 quant-ph hep-exhep-ph

Entanglement and quantum tomography with top quarks at the LHC

classification quant-ph hep-exhep-ph
keywords quantumentanglementexperimentaldetectionhigh-energypairaspectscolliders
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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Entanglement is a central subject in quantum mechanics. Due to its genuine relativistic behavior and fundamental nature, high-energy colliders are attractive systems for the experimental study of fundamental aspects of quantum mechanics. We propose the detection of entanglement between the spins of top-antitop-quark pairs at the LHC, representing the first proposal of entanglement detection in a pair of quarks, and also the entanglement observation at the highest energy scale so far. We show that entanglement can be observed by direct measurement of the angular separation between the leptons arising from the decay of the top-antitop pair. The detection can be achieved with high statistical significance, using the current data recorded during Run 2 at the LHC. In addition, we develop a simple protocol for the quantum tomography of the top-antitop pair. This experimental technique reconstructs the quantum state of the system, providing a new experimental tool to test theoretical predictions. Our work explicitly implements canonical experimental techniques in quantum information in a two-qubit high-energy system, paving the way to use high-energy colliders to also study quantum information aspects.

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