@article{40b81174fc764bf3a657018814a2bba8,
title = "Observation of quantum entanglement with top quarks at the ATLAS detector",
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 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.",
author = "{The ATLAS Collaboration} and L. Zwalinski and W. Zou and O. Zormpa and Zorbas, {T. G.} and K. Zoch and A. Zoccoli and L. {\v Z}ivkovi{\'c} and M. Ziolkowski and J. Zinsser and Zimine, {N. I.} and K. Zhukov and X. Zhuang and Y. Zhu and J. Zhu and Zhu, {C. G.} and Y. Zhou and N. Zhou and H. Zhou and B. Zhou and D. Zhong and Z. Zheng and X. Zheng and K. Zheng and J. Zheng and A. Zhemchugov and Z. Zhao and Y. Zhao and T. Zhao and H. Zhao and Z. Zhang and Y. Zhang and X. Zhang and T. Zhang and S. Zhang and R. Zhang and P. Zhang and L. Zhang and K. Zhang and J. Zhang and Zhang, {D. F.} and M. Zhai and D. Zerwas and S. Zerradi and S. Zenz and T. {\v Z}eni{\v s} and O. Zenin and Zenger, {D. T.} and Zeng, {J. C.} and H. Zeng and C. Zeitnitz and O. Zaplatilek and D. Zanzi and J. Zang and Saa, {J. A.Zamora} and S. Zambito and N. Zakharchuk and T. Zakareishvili and Zak, {Z. K.} and E. Zaid and B. Zabinski and M. Zaazoua and L. Yue and R. Yuan and M. Yuan and Y. Yu and C. Yu and C. Young and Young, {C. J.S.} and S. Younas and K. Yorita and P. Yin and Yexley, {M. R.} and B. Yeo and I. Yeletskikh and Y. Yeh and X. Ye and S. Ye and J. Ye and H. Ye and Yao, {W. M.} and Z. Yang and Y. Yang and X. Yang and T. Yang and S. Yang and Yang, {H. T.} and Yang, {H. J.} and Z. Yan and S. Yan and J. Yan and Y. Yamazaki and T. Yamazaki and H. Yamauchi and E. Yamashita and Y. Yamaguchi and S. Yacoob and B. Yabsley and Z. Xu and Y. Xu and T. Xu and R. Xu and L. Xu and H. Xu and D. Xu and J. Xiong and A. Xiong and S. Xin and X. Xie and M. Xie and J. Xiang and M. Xia and L. Xia and S. Xella and Wynne, {B. M.} and Wyatt, {T. R.} and J. Wuerzinger and Z. Wu and Y. Wu and X. Wu and Wu, {S. L.} and M. Wu and J. Wu and C. Wu and K. Wraight and S. Wozniewski and Wo{\'z}niak, {K. W.} and Wosiek, {B. K.} and Worm, {S. D.} and Woodward, {E. L.} and H. Wolters and Wolter, {M. W.} and J. Wollrath and Z. Wolffs and M. Wobisch and M. Wittgen and Winter, {J. K.} and Winter, {B. T.} and F. Winklmeier and Winkel, {F. I.} and Windischhofer, {P. J.} and Wilson, {B. J.} and S. Willocq and S. Williams and Williams, {H. H.} and Williams, {D. M.} and Wilkens, {H. G.} and Wilbern, {D. J.} and C. Wiglesworth and M. Wielers and W. Wiedenmann and L. Wickremasinghe and D. Whiteson and White, {M. J.} and A. White and White, {A. S.} and Wharton, {A. M.} and M. Wessels and N. Wermes and Wenke, {N. S.} and T. Wengler and B. Wendland and T. Wenaus and Wells, {C. J.} and C. Weiser and M. Weirich and J. Weingarten and Weik, {E. J.} and Weidberg, {A. R.} and Y. Wei and C. Wei and Weber, {M. S.} and Weber, {M. S.} and Weber, {H. A.} and C. Weber and Waugh, {B. M.} and G. Watts and E. Watton and Watson, {M. F.} and H. Watson and Watson, {A. T.} and S. Waterhouse and N. Warrack and Ward, {R. J.} and A. Warburton and Z. Wang and Z. Wang and Z. Wang and Y. Wang and X. Wang and W. Wang and Wang, {W. T.} and T. Wang and S. Wang and Wang, {S. M.} and R. Wang and Wang, {R. J.} and J. Wang and H. Wang and C. Wang and Wang, {A. Z.} and T. Wamorkar and A. Wall and W. Walkowiak and R. Walker and J. Walder and M. Wakida and H. Wahlberg and S. Wahdan and W. Wagner and Wagner, {J. M.} and C. Wagner and S. Wada and I. Vukotic and O. Vujinovic and R. Vuillermet and Vu, {N. K.} and M. Vreeswijk and Milosavljevic, {M. Vranjes} and N. Vranjes and L. Vozdecky and M. Vozak and K. Voss and M. Vos and K. Vorobev and V. Vorobel and B. Vormwald and {Von Toerne}, E. and {Von Ahnen}, J. and Yu Volkotrub and P. Vokac and Voigt, {J. C.} and F. Vogel and E. Voevodina and I. Vivarelli and C. Vittori and A. Visibile and A. Vishwakarma and Virdee, {G. S.} and Vincter, {M. G.} and E. Vilucchi and Villhauer, {E. M.} and Perez, {M. Villaplana} and M. Villa and L. Vigani and Viehhauser, {G. H.A.} and Boeriu, {O. E.Vickey} and T. Vickey and Maira, {N. Viaux} and A. Vgenopoulos and J. Shojaii",
note = "Copyright the Author(s) 2024. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.",
year = "2024",
month = sep,
day = "19",
doi = "10.1038/s41586-024-07824-z",
language = "English",
volume = "633",
pages = "542--547",
journal = "Nature",
issn = "0028-0836",
publisher = "Nature Publishing Groups",
number = "8030",
}