Decoherence in a single trapped ion due to engineered reservoir
  The decoherence in trapped ion induced by coupling the ion to the engineered reservoir is studied in this paper. The engineered reservoir is simulated by random variations in the trap frequency, and the trapped ion is treated as a two-level system driven by a far off-resonant plane wave laser field. The dependence of the decoherence rate on the amplitude of the superposition state is given. 
X. X. Yi, D. L. Zhou, C. P. Sun