Elimination of two-level atom''''s decoherence by an external driving field in degenerate two-photon processes
消除简并双光子过程中二能级原子的消相干性

We have studied the problem of decoherence of two-level atoms which are put in a thermal reservoir through an external controllable driving field. The non-opposite angle element of two-level atom's reducible density rectangular array is obtained. We discuss the properties of an external driving field when the atom's decoherence is eliminated.