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Observation of quantum entanglement with top quarks at the ATLAS detector

Aad, G. ; Åkesson, T.P.A. LU orcid ; Doglioni, C. LU ; Ekman, P.A. LU orcid ; Hedberg, V. LU ; Herde, H. LU orcid ; Konya, B. LU ; Lytken, E. LU orcid ; Poettgen, R. LU orcid and Simpson, N.D. LU , et al. (2024) In Nature 633(8030). p.542-547
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... (More)
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 (Less)
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type
Contribution to journal
publication status
published
subject
keywords
Elementary Particles, Protons, Quantum Theory, proton, collision, data set, energy management, experimental study, Monte Carlo analysis, quantum mechanics, scale effect, Article, astronomy, cryptography, hadron, large hadron collider, luminance, metrology, polarization, quantum computation, quantum entanglement, quantum information, elementary particle, quantum theory
in
Nature
volume
633
issue
8030
pages
6 pages
publisher
Nature Publishing Group
external identifiers
  • scopus:85204418526
  • pmid:39294352
ISSN
0028-0836
DOI
10.1038/s41586-024-07824-z
language
English
LU publication?
yes
id
dcfdfb72-9a87-4b3b-b13c-9f9820bbdc23
date added to LUP
2025-12-04 08:52:31
date last changed
2025-12-05 03:41:41
@article{dcfdfb72-9a87-4b3b-b13c-9f9820bbdc23,
  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}},
  author       = {{Aad, G. and Åkesson, T.P.A. and Doglioni, C. and Ekman, P.A. and Hedberg, V. and Herde, H. and Konya, B. and Lytken, E. and Poettgen, R. and Simpson, N.D. and Smirnova, O. and Zwalinski, L.}},
  issn         = {{0028-0836}},
  keywords     = {{Elementary Particles; Protons; Quantum Theory; proton; collision; data set; energy management; experimental study; Monte Carlo analysis; quantum mechanics; scale effect; Article; astronomy; cryptography; hadron; large hadron collider; luminance; metrology; polarization; quantum computation; quantum entanglement; quantum information; elementary particle; quantum theory}},
  language     = {{eng}},
  number       = {{8030}},
  pages        = {{542--547}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Nature}},
  title        = {{Observation of quantum entanglement with top quarks at the ATLAS detector}},
  url          = {{http://dx.doi.org/10.1038/s41586-024-07824-z}},
  doi          = {{10.1038/s41586-024-07824-z}},
  volume       = {{633}},
  year         = {{2024}},
}