Inhibiting decoherence of two-level atom in thermal bath by presence of   boundaries
  We study, in the paradigm of open quantum systems, the dynamics of quantum coherence of a static polarizable two-level atom which is coupled with a thermal bath of fluctuating electromagnetic field in the absence and presence of boundaries. The purpose is to find the conditions under which the decoherence can be inhibited effectively. We find that without boundaries, quantum coherence of the two-level atom inevitably decreases due to the effect of thermal bath. However, the quantum decoherence, in the presence of a boundary, could be effectively inhibited when the atom is transversely polarizable and near this boundary. In particular, we find that in the case of two parallel reflecting boundaries, the atom with a parallel dipole polarization at arbitrary location between these two boundaries will be never subjected to decoherence provided we take some special distances for the two boundaries. 
Xiaobao Liu, Zehua Tian, Jieci Wang, Jiliang Jing
quant-ph