Observation of spin-dependent quantum jumps via quantum dot resonance fluorescence
Observation of spin-dependent quantum jumps via quantum dot resonance fluorescence
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DOI：
10.1038/nature09359
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发表时间：
2010-09-16
期刊：
影响因子：
64.8
通讯作者：
Atatuere, M.
中科院分区：
文献类型：
--
作者：
Vamivakas, A. N.;Lu, C. -Y.;Atatuere, M.
可靠的准备、操作和测量协议是将物理系统用作量子比特(1)所必需的。光学活性量子点中的自旋提供了一种潜在的实现(2，3)，最近的演示显示了高保真准备(4，5)和超快相干操纵(6-8)。最后一个挑战--即单次测量电子自旋--已被证明是三个挑战中最困难的，到目前为止只报告了时间平均光学测量(9-12)。在单量子点中进行光学自旋读出的主要障碍是，探测自旋态的同一激光器也会反转被测量的自旋。在这里，通过使用门控制的量子点分子(13-15)，我们提出了通过量子点共振荧光(12，16)的间歇性来实时测量单电子的自旋态的能力。与单量子点分子不同，量子点分子允许单独和独立的光学跃迁来进行状态准备、操作和测量，从而避免了依赖相同的跃迁来解决电子自旋态的两难境地。
Reliable preparation, manipulation and measurement protocols are necessary to exploit a physical system as a quantum bit(1). Spins in optically active quantum dots offer one potential realization(2,3) and recent demonstrations have shown high-fidelity preparation(4,5) and ultrafast coherent manipulation(6-8). The final challenge-that is, single-shot measurement of the electron spin-has proved to be the most difficult of the three and so far only time-averaged optical measurements have been reported(9-12). The main obstacle to optical spin readout in single quantum dots is that the same laser that probes the spin state also flips the spin being measured. Here, by using a gate-controlled quantum dot molecule(13-15), we present the ability to measure the spin state of a single electron in real time via the intermittency of quantum dot resonance fluorescence(12,16). The quantum dot molecule, unlike its single quantum dot counterpart, allows separate and independent optical transitions for state preparation, manipulation and measurement, avoiding the dilemma of relying on the same transition to address the spin state of an electron.