Positive noise cross-correlation in hybrid superconducting and normal-metal three-terminal devices
Positive noise cross-correlation in hybrid superconducting and normal-metal three-terminal devices
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DOI：
10.1038/nphys1669
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发表时间：
2010-07-01
期刊：
影响因子：
19.6
通讯作者：
Chandrasekhar, V.
中科院分区：
文献类型：
--
作者：
Wei, Jian;Chandrasekhar, V.
非定域纠缠是量子信息处理的一个关键因素。对于光子，纠缠已经被证明（1），但对于电子，它更难观察。一种方法是使用超导体，其中电子形成自旋纠缠的库珀对，这是纠缠电子的天然来源。对于由夹在两个正常金属之间的超导体组成的三端器件，已经预测库珀对可以分裂成在两个空间分离的正常金属中流动的自旋纠缠电子（2-5），导致负的非局部电阻和正的电流-电流相关性（6，7）。前繁荣已被观察到（8，9），但不是后者。在这里，我们表明，这两个特点可以观察到，符合库珀对分裂。此外，分裂效率可以通过独立控制通过两个超导体/正常金属界面的电子的能量来调节，这可能会导致更好地理解和控制非局域纠缠。
Non-local entanglement is a key ingredient to quantum information processing. For photons, entanglement has been demonstrated(1), but it is more difficult to observe for electrons. One approach is to use a superconductor, where electrons form spin-entangled Cooper pairs, which is a natural source for entangled electrons. For a three-terminal device consisting of a superconductor sandwiched between two normal metals, it has been predicted that Cooper pairs can split into spin-entangled electrons flowing in the two spatially separated normal metals(2-5), resulting in a negative non-local resistance and a positive current-current correlation(6,7). The former prosperity has been observed(8,9), but not the latter. Here we show that both characteristics can be observed, consistent with Cooper-pair splitting. Moreover, the splitting efficiency can be tuned by independently controlling the energy of the electrons passing the two superconductor/normal-metal interfaces, which may lead to better understanding and control of non-local entanglement.