Evidence of macroscopically entangled protons in a mixed isotope crystal of KH$_{p}$D$_{1-p}$CO$_3$

François Fillaux (1) , Alain Cousson (2) , Matthias J. Gutmann (3)

1 LADIR - Laboratoire de Dynamique Interactions et Réactivité
2 LLB - UMR 12 - Laboratoire Léon Brillouin
3 RAL - STFC Rutherford Appleton Laboratory

We examine whether protons and deuterons in the crystal of KH$_{0.76}$D$_{0.24}$CO$_3$ at 300 K are particles or matter waves. The neutron scattering function measured over a broad range of reciprocal space reveals the enhanced diffraction pattern anticipated for antisymmetrized macroscopic states for protons (fermions). These features exclude a statistical distribution of protons and deuterons. Raman spectra are consistent with a mixture of KHCO$_3$ and KDCO$_3$ sublattices whose isomorphous structures are independent of the isotope content. We propose a theoretical framework for decoherence-free proton and deuteron states.

Mots clés: Quantum entanglement; Single crystal; Neutron scattering; Raman scattering; Hydrogen bonding

Domaines: Autre [cond-mat.other]

François Fillaux, Alain Cousson, Matthias J. Gutmann. Evidence of macroscopically entangled protons in a mixed isotope crystal of KH$_{p}$D$_{1-p}$CO$_3$. Journal of Physics: Condensed Matter, 2010, 22, pp.045402. ⟨hal-00446216⟩