Entanglement dynamics in two-proton decay of 12O and 6Be

Yoshiteru Sato

Tomohiro Oishi

This paper presents a theoretical evaluation of spin correlation in the two-proton (2 p ) radioactive emission . The three-body model of 6 Be with the proton-proton interaction, which is adjusted to reproduce the experimental energy release, is utilized. Time-dependent calculations are performed to compute the coupled-spin state of the emitted two protons. The spin-correlation function S as the Clauser-Horne-Shimony-Holt (CHSH) indicator is evaluated as | S | ≅ 2.65 . Namely, the 2 p -spin correlation beyond the limit of local-hidden-variable (LHV) theory is suggested. This correlation is sensitive to the proton-proton interaction. The short-lived (broad-width) 2 p state has the weaker spin correlation. In parallel, the core-proton interactions do not harm this correlation during the time-dependent decaying process. The CHSH measurement can be a novel probe into the effective nuclear interaction inside finite systems. Two-proton emitters can provide a testing field for the identical-particle entanglement.

Oishi, Tomohiro

Open-print version of dissertation thesis. This thesis focuses on the relation between the diproton correlation and the two-proton emission with quantum entanglement. For this purpose, I developed a time-dependent three-body (proton-proton-core) model, where one Cooper pair of protons move inside the mean-field potential. The time-dependent calculation based on the three-body model provides an intuitive way to describe the quantum dynamics of the entangled fermionic pair. It has been shown that, by considering the Cooper-pairing correlation in the initial state of the two protons, (i) the experimental 2p-decay width of Be-6 is well reproduced, and (ii) the two protons are emitted mainly as a diproton-like cluster with the spin-singlet configuration in the early stage of the emission. Hence, the two-proton emission can provide an access to the diproton correlation. This thesis presented the first step to theoretically investigate the diproton correlation as well as quantum entanglement in the time-dependent radioactive emission. [NOTE] In this open-print version, several Figures were inevitably eliminated, because of the copyright and/or file-size problems. Several minor corrections have been done, but without changing the scientific discussions, results, and conclusions from the original version in 2014.

新太郎 青木

K. Lewin

Deuteron photo-decay with subsequent proton detection represents an experiment similar to Bohm’s version of the EPR arrangement replacing the entangled spin singlet state of the two-fermion system by entangled isospin states. Dropping the conception of truth, the detection as charge symmetry breaking event a posteriori leads up to a pre-existing proton identifying the second possibly far apart nucleon as neutron. That explains what the entangled isospin state predicts without assumption of a superluminal correlation.