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Zhi-Chao Ruan

Publications and source records attributed to Zhi-Chao Ruan.

2 recordsLinked to original sources

Explicit formula for the external driving field used to eliminate the decoherence of a two-state system coupled to a noise field

The elimination of decoherence of a multiphoton two-state quantum system by using an appropriate external driving field is considered. The multiphoton process caused by the noise field has a supersymmetric Lie algebraic structure. The time-evolution equations for the off-diagonal elements of the density operator of the two-state system are derived in the interaction picture. A simple explicit formula is given for the time-dependent external driving field used to eliminate the decoherence of the multiphoton two-state system.

quant-ph↗

Influence of the signal light on the transient optical properties of a four-level EIT medium

General formulae for the transient evolution of the susceptibility (absorption) induced by the quantum interference effect in a four-level N-type EIT medium is presented. The influence of the signal light on the transient susceptibility for the probe beam is studied for two typical cases when the strength of the coupling beam is much greater or less than that of the signal field. An interesting level reciprocity relationship between these two cases is found.

quant-ph↗