Evidence Of Macroscopically Entangled Protons In A Mixed Isotope Crystal Of Khpd1-Pco3

We examine whether protons and deuterons in a crystal of KH0.76D0.24CO3 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 KHCO3 and KDCO3 sublattices whose isomorphous structures are independent of the isotope content. We propose a theoretical framework for decoherence-free proton and deuteron states.