Quenching of antihydrogen gravitational states by surface charges
  We study an effect of quenching of antihydrogen quantum states near material surface in the gravitational field of the Earth by local charges randomly distributed along the mirror surface. The quenching mechanism reduces the quantum reflection probability because of additional atom-charge interaction and nonadiabatic transitions to excited gravitational states. Our approach is suitable for accounting for quenching caused by any kind of additional interaction with the characteristic range much smaller than the typical gravitational state wave-length. 
A.Yu. Voronin, E.A. Kupriyanova, A. Lambrecht, V.V. Nesvizhevsky, S.   Reynaud
quant-ph