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arXiv:2606.24468

Entanglement of momenta at colliders

Marco Fabbrichesi, Roberto Floreanini, Luca Marzola

hep-phhep-exquant-phSubmitted Jun 23, 2026• Announced Jun 24, 2026• 0 citations• Revised Oct 27, 2026 (v2)
v1 · Jun 23, 2026v2 · Oct 27, 2026
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Abstract

We investigate the entanglement in the momenta of particle pairs produced at colliders, discarding the information on their spin state. We show how to quantify this entanglement by reducing the continuous momentum variables to a two-qubit system through hemispherical projections. We discuss in detail the production of $τ$-lepton pairs at an electron collider. In the Standard Model, the discretized momenta are in a genuinely maximally entangled pure state for suitable choices of the hemispheres.

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11 pages

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We investigate the entanglement in the momenta of particle pairs produced at colliders, discarding the information on their spin state. We show how to quantify this entanglement by reducing the continuous momentum variables to a two-qubit system through hemispherical projections. We discuss in detail the production of τττ-lepton pairs at an electron collider. In the Standard Model, the discretized momenta are in a genuinely maximally entangled pure state for suitable choices of the hemispheres.
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Momentum entanglement at colliders: the H→WW,ZZH \to WW,ZZH→WW,ZZ case
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Tripartite Entanglement in e+e−→ttˉZe^+ e^- \to t \bar{t} Ze+e−→ttˉZ
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