Entanglement is a key feature of quantum mechanics1-3, with applications in fields such as metrology, cryptography, quantum information and quantum computation4-8. It has been observed in a wide variety of systems and length scales, ranging from the microscopic9-13 to the macroscopic14-16. However, entanglement remains largely unexplored at the highest accessible energy scales. Here we report the highest-energy observation of entanglement, in top-antitop quark events produced at the Large Hadron Collider, using a proton-proton collision dataset with a centre-of-mass energy of √s = 13 TeV and an integrated luminosity of 140 inverse femtobarns (fb)-1 recorded with the ATLAS experiment. Spin entanglement is detected from the measurement of a single observable D, inferred from the angle between the charged leptons in their parent top- and antitop-quark rest frames. The observable is measured in a narrow interval around the top-antitop quark production threshold, at which the entanglement detection is expected to be significant. It is reported in a fiducial phase space defined with stable particles to minimize the uncertainties that stem from the limitations of the Monte Carlo event generators and the parton shower model in modelling top-quark pair production. The entanglement marker is measured to be D = -0.537 ± 0.002 (stat.) ± 0.019 (syst.) for 340GeV<380GeV . The observed result is more than five standard deviations from a scenario without entanglement and hence constitutes the first observation of entanglement in a pair of quarks and the highest-energy observation of entanglement so far.

Observation of quantum entanglement with top quarks at the ATLAS detector / G. Aad, B.A.. - In: NATURE. - ISSN 0028-0836. - 633:8030(2024), pp. 542-547. [10.1038/s41586-024-07824-z]

Observation of quantum entanglement with top quarks at the ATLAS detector

A. Andreazza;A. Carbone;L. Carminati;S. D'Auria;L. Dell'Asta;M. Fanti;M. Lazzaroni;E. Mazzeo;C. Meroni;F. Ragusa;
2024

Abstract

Entanglement is a key feature of quantum mechanics1-3, with applications in fields such as metrology, cryptography, quantum information and quantum computation4-8. It has been observed in a wide variety of systems and length scales, ranging from the microscopic9-13 to the macroscopic14-16. However, entanglement remains largely unexplored at the highest accessible energy scales. Here we report the highest-energy observation of entanglement, in top-antitop quark events produced at the Large Hadron Collider, using a proton-proton collision dataset with a centre-of-mass energy of √s = 13 TeV and an integrated luminosity of 140 inverse femtobarns (fb)-1 recorded with the ATLAS experiment. Spin entanglement is detected from the measurement of a single observable D, inferred from the angle between the charged leptons in their parent top- and antitop-quark rest frames. The observable is measured in a narrow interval around the top-antitop quark production threshold, at which the entanglement detection is expected to be significant. It is reported in a fiducial phase space defined with stable particles to minimize the uncertainties that stem from the limitations of the Monte Carlo event generators and the parton shower model in modelling top-quark pair production. The entanglement marker is measured to be D = -0.537 ± 0.002 (stat.) ± 0.019 (syst.) for 340GeV<380GeV . The observed result is more than five standard deviations from a scenario without entanglement and hence constitutes the first observation of entanglement in a pair of quarks and the highest-energy observation of entanglement so far.
Settore PHYS-01/A - Fisica sperimentale delle interazioni fondamentali e applicazioni
Settore IMIS-01/B - Misure elettriche ed elettroniche
2024
18-set-2024
https://www.nature.com/articles/s41586-024-07824-z#citeas
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/1099629
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