A theoretical study asks whether a high-energy arrangement of three protons could produce a simple, potentially measurable signature associated with spin-state teleportation. The modeled setup combines two entangled protons, labeled 2 and 3, with proton 1 in a hydrogen target. The target’s polarization, meaning its preferred spin direction, is treated as an input to the calculation.
The work is an arXiv version 1 preprint in the nucl-th category, posted on 28 August 2026 and dated 31 August 2026. It reports calculations rather than an experimental result. For proton-proton scattering, spin observables are obtained from final spin-density matrices after solving the Lippmann-Schwinger equation with the AV18 nucleon-nucleon potential and an explicit Coulomb interaction.
The breakup part uses three-nucleon Faddeev calculations with the AV18 interaction, in versions with and without the Coulomb force. The modeled process is a final-state-interaction, or FSI, breakup, and a Monte Carlo simulation is mentioned as a feasibility check comparing proton-deuteron and neutron-deuteron breakup cross sections as the FSI production angle changes.
A narrow window for the transfer
At an incoming laboratory energy of 350 MeV and an FSI production angle of 9.1°, the calculated deuteron-breakup configuration produces a minus Bell-state proton pair, with each proton at 150.9 MeV. The outgoing neutron is calculated to appear at 144.9° with an energy of 46 MeV. These figures describe selected model kinematics, not an experimental yield.
In the second scattering, single-term dominance is treated as a good approximation near 151 MeV only within the narrow 85° to 95° strong-entanglement interval. Within that region, the calculated polarization-transfer coefficient from target proton 1 to output proton 3′ is negative one. In ordinary terms, proton 3′ is predicted to have a polarization equal in magnitude but opposite in sign to the target proton.
The idealized spin picture is cleaner than the full numerical result. Under the single-term approximation, outgoing protons 1′ and 2′ have a spin correlation of +1 and are identified with the psi-plus Bell state. The other pair correlations and single-spin correlation transfers vanish in that approximation. In the numerical strong-entanglement region, however, the 1′3′ and 2′3′ correlations are nearly equal at about -0.2. The text attributes those residual values to additional Bell-state components, and the approximate value is reported without an uncertainty interval.
The EPR-like test has a different problem
The study also proposes an EPR-like polarization test. For an unpolarized hydrogen target, the model links the scattered proton’s angle-dependent induced polarization to an equal-magnitude induced polarization in the entangled partner that does not scatter. The sign of the Bell-state correlation determines whether the two polarizations match or oppose.
The proposed 151 MeV proton-proton scenario uses a psi-plus pair, with both entangled protons at 75.5 MeV and emerging at laboratory angles of 45°. Their initial individual polarizations are zero, while their initial spin correlation is +1. The unscattered proton is expected to share the scattered proton’s induced polarization. The proposed readout uses left-right scattering from a target with known proton analyzing power.
The direct proton-proton arrangement is nevertheless described as unsuitable for the teleportation requirement. The 75.5 MeV proton used in the second scattering lies outside the energy region where a single Bell-state term is a good approximation, and the calculated pair correlations generally deviate from +1.
The result still needs an experiment
The preprint presents calculated signatures rather than measurements. Its central transfer relation depends on single-Bell-term dominance in a narrow energy and angle range, while the proposed FSI route has not been experimentally validated. Whether the predicted signals can be measured with realistic targets, known analyzing powers, detectors and sufficient breakup yield remains open.
The work reports support from Poland’s National Science Centre through grant IMPRESS-U 2024/06/Y/ST2/00135. It also reports that numerical calculations were partly performed on JSC supercomputers in Jülich, Germany. The manuscript remains an arXiv version 1 preprint.
Paper data and sources
Original title: Spin-State Teleportation and Tests of EPR Correlations Using 151 MeV Entangled Protons
Authors: H. Witała
Journal/Repository: arXiv
Status: Preprint, not yet peer-reviewed
First online: 2026-08-28
DOI: Not available
Original paper · Full text