三量子位系统的消相干和退纠缠

基于多谐振子热库环境模型,采用求解非马尔可夫近似主方程方法,研究了三量子位系统由于相对位相变化引起的消相干和退纠缠.计算得到了初始态为GHZ-class态、W-class态和WGHZ-class态在演化过程中的消相干和退纠缠时间尺度.结果表明,对初始GHZ-class态,相干性全部丧失,退纠缠完全发生,纠缠度变为0；对初始W-class态,相干性和纠缠度被保持；对初始WGHZ-class态,消相干部分发生,纠缠首先随时间变化最后达到一个渐近值.

Disentanglement and Decoherence in the Three-qubit System

The disentanglement and decoherence in the three-qubit system are studied based on the model of reservoir of harmonic oscillators by solving the non-Markovian approximation master equation, in which they are caused by a pure dephasing process. The GHZ-class state, W-class state and WGHZ-class state are discussed in detail. In all cases, the time scales of the decoherence and disentanglement are obtained. For the initial GHZ-class state, the coherence and entanglement decay completely; for the initial W-class state, the decoherence and disentanglement do not occur; for the initial WGHZ-class state, the decoherence happens partly, and the entanglement varies with time firstly and then becomes a certain asymptotic value.