Abstract:We analyze the achievable limits of the quantum information processing of the weak interaction revealed by hyperons with spin. We find that the weak decay process corresponds to an interferometric device with a fixed visibility and fixed phase difference for each hyperon. Nature chooses rather low visibilities expressing a preference to parity conserving or violating processes (except for the decay Σ+→ pπ0). The decay process can be considered as an open quantum channel that carries the information of the hype… Show more
“…35 , double slit-like experiments attain a unified description in terms of the a priori visibility and the a priori predictability 36–39 , the “ which way ” information. This includes the decay of neutral mesons, spin systems in magnetic fields or typical interferometric setups or the decay of hyperons 40 . The a priori visibility may be interpret to present the “wave particle” property, whereas the predictability captures the “particle property”, and Bohr’s complementarity relation becomes quantified since the general relation has to hold (equality holds for pure states).Figure 2The plots (left graphic) show the visibility in dependence of Compton scattering angle for different initial energies k i .…”
We present a quantum information theoretic version of the Klein-Nishina formula. This formulation singles out the quantity, the
a priori
visibility, that quantifies the ability to deduce the polarisation property of single photons. The Kraus-type structure allows a straightforward generalisation to the multiphoton cases, relevant in the decay of positronium which is utilized e.g. for metabolic PET-imaging (Positron- Emission- Tomograph). Predicted by theory but never experimentally proven, the two- or three-photon states should be entangled. We provide an experimentally feasible method to witness entanglement for these processes via MUBs (Mutually Unbiased Bases), exploiting Bohr’s complementarity. Last but not least we present explicit cases exemplifying the interrelation of geometry and entanglement including relations to its potentiality for teleportation schemes or Bell inequality violations or in future for detecting cancer in human beings.
“…35 , double slit-like experiments attain a unified description in terms of the a priori visibility and the a priori predictability 36–39 , the “ which way ” information. This includes the decay of neutral mesons, spin systems in magnetic fields or typical interferometric setups or the decay of hyperons 40 . The a priori visibility may be interpret to present the “wave particle” property, whereas the predictability captures the “particle property”, and Bohr’s complementarity relation becomes quantified since the general relation has to hold (equality holds for pure states).Figure 2The plots (left graphic) show the visibility in dependence of Compton scattering angle for different initial energies k i .…”
We present a quantum information theoretic version of the Klein-Nishina formula. This formulation singles out the quantity, the
a priori
visibility, that quantifies the ability to deduce the polarisation property of single photons. The Kraus-type structure allows a straightforward generalisation to the multiphoton cases, relevant in the decay of positronium which is utilized e.g. for metabolic PET-imaging (Positron- Emission- Tomograph). Predicted by theory but never experimentally proven, the two- or three-photon states should be entangled. We provide an experimentally feasible method to witness entanglement for these processes via MUBs (Mutually Unbiased Bases), exploiting Bohr’s complementarity. Last but not least we present explicit cases exemplifying the interrelation of geometry and entanglement including relations to its potentiality for teleportation schemes or Bell inequality violations or in future for detecting cancer in human beings.
“…Study of baryon-antibaryon pair production involving isospin-1 baryons such as Σ can help to understand the dynamics of the final-state interactions leading to the nonzero ΔΦ phase. The process + − → / , → Σ + Σ − studied using the Σ (Σ + → 0 ) decay mode is interesting in the context of revealing quantum entangled spin correlations, since the large value of the asymmetry parameter | Σ | ≈ 1 makes some of the quantum mechanics tests possible [40]. The PDG18 value of the decay parameter Σ given in Table 1 was based on the + → Σ + + experiments fifty years ago [41][42][43] while Σ has not been measured.…”
A novel multidimensional method to study hyperon and antihyperon decays and to search for a direct CP-violation signal is presented. The method uses spin polarization and entanglement of baryon-antibaryon pairs produced in electron-positron annihilation at the / and resonances. The method was applied in a series of proof-of-concept analyses at BESIII. The helicity amplitudes describing electron-positron annihilation into ΛΛ, Σ + Σ − , Ξ − Ξ + and Ω − Ω + pairs at / or were determined. A significant transverse polarization of the (anti)hyperons in / and decays was observed and spin of the Ω − baryon was determined in a model independent way using the reaction properties. The asymmetry parameters of the main (anti)hyperon decay modes, the nonleptonic two-body decays, were precisely measured. The result for the asymmetry parameter Λ in Λ → − revises by 17% the value used for nearly 50 years in all analyses of Λ polarization.Additionally, in the sequential weak decays Ξ − → Λ − and Ω − → Λ − the spin rotation parameter was measured.A comparison of the hyperon and antihyperon decay parameters allows for tests of direct CPsymmetry violation, that are complementary to the / measurement in kaon decays. Of special importance are the new results on + − → / → Ξ − Ξ + , where the final-state interaction and weak-phase difference are disentangled. Prospects of future measurements at Super Charm-Tau Factories are discussed with the emphasis on the impact of the longitudinal polarization of the electron beams on the precision of the CP-violation tests.
“…This proposal will be presented in the following section with emphasis on the relation to CP violation. Last but not least we investigate entanglement and Bell's theorem in hyperon-antihyperon systems that are also decaying weakly [23]. This also completes an information theoretic approach to weakly decaying particles and Bell's theorem.…”
Abstract. In 1964 the physicists John St. Bell working at CERN took the 1935-idea of Einstein-Podolsky-Rosen seriously and found that all theories based on local realism have to satisfy a certain inequality, nowadays dubbed Bell's inequality. Experiments with ordinary matter systems or light show violations of Bell's inequality favouring the quantum theory though a loophole free experiment has not yet been performed. This contribution presents an experimentally feasible Bell inequality for systems at higher energy scales, i.e. entangled neutral K-meson pairs that are typically produced in Φ-mesons decays or proton-antiproton annihilation processes. Strong requirements have to be overcome in order to achieve a conclusive tests, such a proposal was recently published. Surprisingly, this new Bell inequality reveals new features for weakly decaying particles, in particular, a strong sensitivity to the combined charge-conjugation-parity ( CP) symmetry. Herewith, a puzzling relation between a symmetry breaking for mesons and Bell's inequality -which is a necessary and sufficient condition for the security of quantum cryptography protocols-is established. This becomes the more important since CP symmetry is related to the cosmological question why the antimatter disappeared after the Big Bang.
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