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Sep28-09, 05:44 AM
P: 44
Can entangled protons be maintained in a crystal lattice for an indefinite period of time?
The following papers seem to support this contention.
I need the help of the Forum’s readers to critique this research and the assertions the authors are making.

Dr. Francois Fillauxa and Dr Alain Cousson in a paper titled "Where are protons and deuterons in KHpD1−pCO3? A neutron diffraction study" have claimed that "defect-free crystals are macroscopic quantum systems with discrete phonon states at any temperature below melting or decomposition. This is an unavoidable consequence of the translational invariance of the lattice." (see

This paper which was published in "Zeitschrift fuer Physikalische Chemie 222, 8-9 (2008) 1279-1290" then proceeds to make the following claims:
"This ground state is intrinsically steady against decoherence. Irradiation by plane waves (photons or neutrons) may single out some excited states. Entanglement in position and momentum is preserved, while the spinsymmetry and super-rigidity are destroyed. However, the spin-symmetry reappears automatically after decay to the ground state, presumably on the time-scale of proton dynamics. Consequently, disentanglement reaches a steady regime such that the amount of transitory disentangled states is determined by the ratio of density-of-states for the surroundings (atmosphere, external radiations...) and for the crystal, respectively. This ratio is so small that disentangled states are too few to be observed. Nevertheless, they allow the super-rigid sublattice to be at thermal equilibrium with the surroundings, despite the lack of internal dynamics. The main source of disentanglement is the thermal population of excited proton states. However, even at room temperature, the thermal population of the first excited state (< 1% for OH ≈ 1000 cm−1) is of little impact to measurements."

In an earlier paper titled "Macroscopic quantum entanglement and ‘super-rigidity’ of protons in the KHCO3 crystal from 30 to 300 K" from the “JOURNAL OF PHYSICS: CONDENSED MATTER” alleged "Quantum entanglement, still observed at 300 K, indicates that proton transfer is a thermally activated coherent superposition of macroscopic tunnelling states. This work adds a crystalline solid to the list of systems with ‘super’ properties.' (see

A third paper titled "Proton transfer in the KHCO3 and benzoic acid crystals: A quantum view" builds on the 2006 paper cited above in the following: "Macroscopic entanglement has been evidenced for KHCO3, from 15 to 300 K, with neutron diffraction [20,22]." and states "In a perfect crystal, atoms are not individual particles possessing properties on their own right. They are entangled. The periodicity and indistinguishablility of lattice sites lead to extended states in three dimensions and nonlocal observables (for example phonons). There is no transition to the classical regime, as long as the crystal is stable, and disorder-free." (see

This paper, which appeared in the Journal of Molecular Structure 844–845 (2007) 308–318, also claims that "There is no local information available for these macroscopically entangled states. In addition, they are intrinsically decoherence-free. Irradiation by photons, neutrons, etc, may single out some excited pseudoprotons, but as long as Eqs. (5) and (8) remain valid, entanglement in position and momentum is preserved. Only the spin-symmetry and super-rigidity, intrinsic to degenerate states, can be destroyed, but these properties are recovered automatically, after decay to the ground state, presumably on the time-scale of proton dynamics. This mechanism allows the sublattice to be at thermal equilibrium with the surroundings, despite the lack of internal dynamics."

If the critique is favorable, the next question I would like to ask is whether the entangled protons might be subject to adiabatic manipulation?
Any insights the readers may wish to share would be valued.

Thank you.
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