约瑟夫森电荷量子比特的耗散特性

The Dissipative Properties of Josephson Charge Qubit

从环境的两种不同初态(粒子数态和热平衡态)出发,对电荷量子比特的时间演化进行了深入的研究。结果表明:在温度较高(500 mK)时,如果环境初始处在粒子数态,那么翻转算符的衰减时间会比热库处于热平衡态时更长,并且|0>态的布居数算符的渐近值也更小。在温度极低(50 mK)时,电荷量子比特的动力学特性就与环境的初态无关。

Beginning with two different initial states for the bath modes （equilibrium states and number states）, time evolution of Josephson charge quantum bit linearly coupled to a heat bath is investigated thoroughly. The couclusion shows： if the bath modes are initially in number states, then decay time of turnable operator is longer and asymptotical value of population operator is smaller than that if the equilibrium states are at high temperature . The dynamic properties of the charge quantum bit are not related to initial states if the bath mode are at low temperature.