We discuss the feasibility of quantum spin-state teleportation in a three-proton system at an energy of 151 MeV, where, similarly to the low-energy case, a single Bell-state term dominates the proton-proton scattering matrix. We find that, in contrast to the low-energy regime, where unpolarized proton-proton scattering produces strongly entangled outgoing proton pairs, at higher energies a pair of protons, each with an energy of
151~MeV, must be produced in an unpolarized, exclusive proton-deuteron breakup reaction under complete final-state-interaction kinematics. The subsequent interaction of one of the entangled protons with a polarized hydrogen target triggers, as in the low-energy case, the teleportation process, whereby the polarization of the target proton is transferred to the second member of the entangled pair within the very narrow angular region of strong entanglement centered around a laboratory scattering angle of
45∘. We also find that scattering one member of a strongly correlated proton pair forming a Bell state from an unpolarized hydrogen target leads to Einstein-Podolsky-Rosen-like correlations between the polarization of the scattered proton and that of the unscattered second entangled proton. The polarization of the scattered proton varies with its scattering angle. An identical polarization, following the angular dependence of thepolarization of the first proton, is induced in the second member of the pair, whose initial polarization was zero and whose momentum remains unchanged. The sign of the polarization of the second proton is determined by the sign of the spin correlation in the Bell state.
We discuss the peculiarities of scattering in a three-proton system induced by the presence of an entangled proton-proton Bell-like state in the initial configuration. We formulate the problem using the standard spin formalism of nuclear physics in order to follow in detail the reaction pathways leading to the teleportation of a quantum-mechanical state within this system. By performing numerical simulations of the system and calculations based on a realistic nucleon-nucleon potential, we evaluate the relevant spin observables and search for a simple, experimentally feasible signal that could provide clear evidence of quantum teleportation. For the case in which proton 2, belonging to the entangled proton pair 23, interacts with hydrogen target 1, thereby triggering the teleportation process, we find clear evidence of teleportation through measurements of the final polarization of proton 3', even for small values of the polarization of target proton 1. The dominant component of this polarization is transferred almost entirely from target proton 1 to proton 3 in the angular region characterized by strong entanglement. For an unpolarized target proton 1, quantum teleportation is no longer possible. The only unambiguous signature of the residual quantum correlations would be provided by measurements of the spin correlations within the strongly entangled final-state proton pair 1'2'. Indirect evidence may also be obtained from measurements of the polarization of proton 2' in the final state, although the corresponding effectis relatively weak.