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arXiv:2606.24468

Entanglement and non-separability of momenta and coordinates at colliders

Marco Fabbrichesi, Roberto Floreanini, Luca Marzola

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

We explore the possibility of testing in collider experiments whether phase-space variables are separable. We first study phase-space non-separability by means of EPR-like correlations. The original EPR setting is realized in an actual experiment, specifically in terms of coordinates and momenta, as per the original formulation, rather than spins or polarizations. We then show how to quantify the entanglement in the momenta of particle pairs by reducing the continuous variables to a two-qubit system through hemispherical projections. We discuss in detail the production of $τ$-leptons at an electron collider, reconstructing the momenta of the former from their decays into pions and neutrinos, and demonstrate through a Monte Carlo simulation that phase-space non-separability can be experimentally assessed.

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Quantum entanglement and Bell nonlocality--cornerstones of quantum mechanics--have traditionally been investigated only in low-energy experimental settings. Only recently, these fundamental phenomena have come to be explored in the high-energy domain of particle physics, where collider experiments offer a powerful new platform for studying the phenomenology of quantum correlations. We present here recent results on the detection of entanglement and Bell nonlocality in processes such as tau-lepton, WWWWWW, and ZZZZZZ pair production, illustrating the potential of Future Lepton Colliders to probe the quantum properties of fundamental interactions.