Short lived protonic quantum entanglement and coupling to the electronic environment in LaH 2 and LaH 3

Abstract

Very recently, a temperature dependent decrease of the protonic neutron scattering cross section σ H in LiH using neutron Compton scattering (NCS) has been reported. The decrease of σ H – which has been found in various materials using different experimental methods – is attributed to short-lived protonic quantum entanglement and it was suggested that the novel temperature dependence is due to the different coupling of the protons to the environment. The exact mechanism of the loss of coherence (i.e. decoherence) of the protonic quantum entangled states due to the interaction with the environment in condensed matter is not fully understood yet. To shed more light onto that, the NCS of LaH 2 and LaH 3 has been measured. While LaH 2 is metallic, LaH 3 is an isolator, thus providing completely different electronic environments the protons are coupled to. The experiment shows that σ H is smaller for LaH 3 than it is for LaH 2. This result strongly suggest that the different couplings of the protons to the different electronic environments lead to different anomalies.