Continuous quantum measurement of two coupled quantum dots using a point contact: A quantum trajectory approach
Continuous quantum measurement of two coupled quantum dots using a point contact: A quantum trajectory approach
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DOI：
10.1103/physrevb.63.125326
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发表时间：
2000-06
影响因子：
3.7
通讯作者：
H. Goan;G. Milburn;H. Wiseman;H. P. Q. Technology;D. Physics;The University of Queensland;Brisbane;Australia. School of Science;Griffith University;Nathan;Australia
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文献类型：
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作者：
H. Goan;G. Milburn;H. Wiseman;H. P. Q. Technology;D. Physics;The University of Queensland;Brisbane;Australia. School of Science;Griffith University;Nathan;Australia
我们得到了两个耦合量子点（CQD's）的密度矩阵的有限温度无条件主方程时，一个点进行测量，其电子占据数使用点接触（PC）。为了确定CQD系统状态如何依赖于通过PC设备的实际电流，我们使用所谓的量子轨道方法来推导零温度条件主方程。我们首先把电子隧穿PC势垒作为一个经典的随机点过程（量子跳跃模型）。然后，我们明确地表明，我们的结果可以扩展到量子扩散极限时，平均电子隧穿率是非常大的相比，额外的变化的隧穿率由于在点的电子的存在更接近PC。我们发现，在量子跳跃和量子扩散的情况下，CQD系统的条件动力学可以描述为随机薛定谔方程的条件状态向量，当且仅当从CQD系统的PC水库带走的信息可以恢复的完美检测的测量。
We obtain the finite-temperature unconditional master equation of the density matrix for two coupled quantum dots (CQD's) when one dot is subjected to a measurement of its electron occupation number using a point contact (PC). To determine how the CQD system state depends on the actual current through the PC device, we use the so-called quantum trajectory method to derive the zero-temperature conditional master equation. We first treat the electron tunneling through the PC barrier as a classical stochastic point process (a quantum-jump model). Then we show explicitly that our results can be extended to the quantum-diffusive limit when the average electron tunneling rate is very large compared to the extra change of the tunneling rate due to the presence of the electron in the dot closer to the PC. We find that in both quantum-jump and quantum-diffusive cases, the conditional dynamics of the CQD system can be described by the stochastic Schrodinger equations for its conditioned state vector if and only if the information carried away from the CQD system by the PC reservoirs can be recovered by the perfect detection of the measurements.