The muon-fluorine interaction: a model quantum system for exploring decoherence*

In non-magnetic fluorides, an implanted muon will stop very close to the highly electronegative fluoride ion, or very often stop between two of them. The dipolar interaction between the fluorine nuclei spins and the muon spin gives rise to a characteristic signature which characterises the state. The remaining fluorine nuclei are more distant and usually ignored, since their coupling to the muon is weaker. We show that taking them properly into account allows one to model the data in greater quantitative detail, understand the stopping site more accurately, and explore how the quantum information held by the state decoheres into its environment.