Habgood Matthew, Jefferson John H, Briggs G Andrew D
QIP IRC Group, Department of Materials, University of Oxford, Parks Road, Oxford, UK.
J Phys Condens Matter. 2009 Feb 18;21(7):075503. doi: 10.1088/0953-8984/21/7/075503. Epub 2009 Jan 29.
A theoretical scheme is presented for the entanglement of two-electron spin qubits bound in series within a quasi-one-dimensional mesoscopic structure at a distance beyond their normal range of interaction. A third electron is scattered from them, and full entanglement is achieved upon measurement of a transmitted electron in the correct spin state. Critically, each bound electron is trapped within an individual structure that has at least two spatial states. Two simple examples of such structures are discussed here. One is a 'stub', in which a quantum dot (for example) is coupled to one side of the quasi-one-dimensional structure. The other is a pair of degenerate, coupled quantum dots, with strong interdot Coulomb repulsion, placed within the one-dimensional superstructure. Both of these are shown to allow generation of entanglement with a significant probability of success. In contrast to the results of the authors' previous works, this allows for the generation of entanglement in a series, rather than in a parallel, configuration of the bound electrons with respect to the propagating electron.
提出了一种理论方案，用于在准一维介观结构中，将两个串联束缚的电子自旋量子比特在超出其正常相互作用范围的距离上进行纠缠。第三个电子从它们那里散射，当测量处于正确自旋态的透射电子时，实现完全纠缠。关键的是，每个束缚电子被困在至少具有两个空间态的单个结构内。这里讨论了这种结构的两个简单例子。一个是“短截线”，其中一个量子点（例如）耦合到准一维结构的一侧。另一个是一对简并的、耦合的量子点，具有很强的点间库仑排斥力，放置在一维超结构内。这两种情况都显示出能够以显著的成功概率产生纠缠。与作者之前工作的结果不同，这允许在束缚电子相对于传播电子的串联配置中产生纠缠，而不是在并联配置中产生纠缠。
