Measuring motion through relativistic quantum effects
  We show that the relativistic signatures on the transition probability of atoms moving through optical cavities are very sensitive to their spatial trajectory. This allows for the use of internal atomic degrees of freedom to measure small time-dependent perturbations in the proper acceleration of an atomic probe, or in the relative alignment of a beam of atoms and a cavity. 
Aida Ahmadzadegan, Robert B. Mann and Eduardo Martin-Martinez
quant-ph gr-qc hep-th