Preservation of coherence for a Two-Level atom tunneling through a   squeezed vacuum with finite bandwidth
  Tunneling of a two-state particle through a squeezed vacuum is considered. It has been shown that repetitive measurement or interaction with the external field can preserve the coherence. Moreover, the coherence time in terms of the squeezing parameters has been calculated. A specific condition is derived, under which the coherence is sustainable. 
Samyadeb Bhattacharya and Sisir Roy
quant-ph