Ultrafast entangling gates between nuclear spins using photoexcited triplet states
Ultrafast entangling gates between nuclear spins using photoexcited triplet states
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DOI：
10.1038/nphys2353
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发表时间：
2012-08-01
期刊：
影响因子：
19.6
通讯作者：
Morton, John J. L.
中科院分区：
文献类型：
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作者：
Filidou, Vasileia;Simmons, Stephanie;Morton, John J. L.
在电子和原子核的自旋中表示信息一直是量子计算机正在进行的发展中的一种强大方法（1，2）。虽然核自旋作为量子比特（qubit）是有利的，因为它们的相干寿命长（超过秒（3）），它们表现出非常慢的自旋相互作用，并具有弱的热极化。耦合的电子自旋可以用来抑制核自旋（4-6）并创建快速单量子位门（7，8），然而，电子自旋的永久存在是核退相干的来源。在这里，我们展示了如何瞬态电子自旋，所产生的光激发三重态的C-60，可以用来hyperplanation，操纵和测量两个附近的核自旋。实现一个使用电子旋量性质的方案（9），我们在数百纳秒内完成了一个纠缠门：比液态J耦合快五个数量级。这种方法可以广泛应用于包括与多个核自旋耦合的电子自旋的系统，例如金刚石中的氮空位中心（10），而瞬态电子自旋的成功使用促使能够利用光激发三重态的新分子的设计。
The representation of information within the spins of electrons and nuclei has been a powerful method in the ongoing development of quantum computers(1,2). Although nuclear spins are advantageous as quantum bits (qubits) because of their long coherence lifetimes (exceeding seconds(3)), they exhibit very slow spin interactions and have weak thermal polarization. A coupled electron spin can be used to polarize the nuclear spin(4-6) and create fast single-qubit gates(7,8), however, the permanent presence of electron spins is a source of nuclear decoherence. Here we show how a transient electron spin, arising from the optically excited triplet state of C-60, can be used to hyperpolarize, manipulate and measure two nearby nuclear spins. Implementing a scheme that uses the spinor nature of the electron(9), we performed an entangling gate in hundreds of nanoseconds: five orders of magnitude faster than the liquid-state J coupling. This approach can be widely applied to systems comprising an electron spin coupled to multiple nuclear spins, such as nitrogen-vacancy centres in diamond(10), while the successful use of a transient electron spin motivates the design of new molecules able to exploit photoexcited triplet states.