TY - JOUR
T1 - Observation of quantum entanglement with top quarks at the ATLAS detector
AU - The ATLAS collaboration
AU - Zwalinski, L.
AU - Zou, W.
AU - Zormpa, O.
AU - Zorbas, T. G.
AU - Zoch, K.
AU - Zoccoli, A.
AU - Živković, L.
AU - Ziolkowski, M.
AU - Zinsser, J.
AU - Zimine, N. I.
AU - Zhukov, K.
AU - Zhuang, X.
AU - Zhu, Y.
AU - Zhu, J.
AU - Zhu, C. G.
AU - Zhou, Y.
AU - Zhou, N.
AU - Zhou, H.
AU - Zhou, B.
AU - Zhong, D.
AU - Zheng, Z.
AU - Zheng, X.
AU - Zheng, K.
AU - Zheng, J.
AU - Zhemchugov, A.
AU - Zhao, Z.
AU - Zhao, Y.
AU - Zhao, T.
AU - Zhao, H.
AU - Zhang, Z.
AU - Zhang, Y.
AU - Zhang, X.
AU - Zhang, T.
AU - Zhang, S.
AU - Zhang, R.
AU - Zhang, P.
AU - Zhang, L.
AU - Zhang, K.
AU - Zhang, J.
AU - Zhang, D. F.
AU - Zhai, M.
AU - Zerwas, D.
AU - Zerradi, S.
AU - Zenz, S.
AU - Ženiš, T.
AU - Zenin, O.
AU - Zenger, D. T.
AU - Zeng, J. C.
AU - Nasri, S.
AU - Belfkir, M.
N1 - Publisher Copyright:
© The Author(s) 2024.
PY - 2024/9/19
Y1 - 2024/9/19
N2 - 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 340GeVtt¯<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.
AB - 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 340GeVtt¯<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.
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UR - http://www.scopus.com/inward/citedby.url?scp=85204418526&partnerID=8YFLogxK
U2 - 10.1038/s41586-024-07824-z
DO - 10.1038/s41586-024-07824-z
M3 - Article
C2 - 39294352
AN - SCOPUS:85204418526
SN - 0028-0836
VL - 633
SP - 542
EP - 547
JO - Nature
JF - Nature
IS - 8030
ER -