INHOMOGENEOUS QUANTUM DIFFUSION

Quantum diffusion of the muonium (Mu) atom has been studied in solid n itrogen crystals using the technique of Mu spin relaxation. At low tem peratures the results are inconsistent with diffusion models using a s ingle correlation time tau(c), instead, the muon polarization exhibits two-component relaxation, which is taken as evidence for the intrinsi c inhomogeneity of Mu dynamics in a spatially inhomogeneous crystal. C onventional trapping mechanisms are shown to be ineffective at low tem peratures in insulators.