Resubmission of IMPRESS: Intra-Molecular Propagation of Electron Spin States

学术界和商业领域都在全球范围内进行着激烈的搜索，以找到一条通向分子尺度结构计算的现实途径。国际半导体技术路线图（public.itrs.net）是电子工业的权威文件，现在认识到传统的“自上而下”技术可能有有限的剩余寿命。它提倡寻找下一代技术，认识到分子尺度计算是一个非常有前途的前景。它进一步强调了量子信息处理（QIP），这种技术将通过操纵状态的相干叠加而产生，在某些应用中具有巨大的潜力。我们在这里描述的研究旨在为这些类别的技术创建原型元素。IMPRESS项目关注的是单个纳米结构中的电子自旋态，特别是碳纳米管“豆荚”。通过各种表征技术和开创性的合成化学，我们将发展沿着管内自旋一维链设计自旋相互作用的能力。最近备受瞩目的理论研究表明，这样的自旋链将具有非常显著的性质。它将能够沿链快速传递自旋态，即信息，纯粹依靠自旋-自旋相互作用，而不需要任何外部施加的电压或功耗。此外，甚至有可能通过这种链的自由演化产生多自旋纠缠，这是QIP的潜在资源。因此，这种分子装置可以构成任何基于电子自旋的信息处理技术的关键组成部分，尤其是量子量子ip。

There is an intense worldwide search, spanning both academic and commercial sectors, to find a realistic route toward computing with molecular scale structures. The International Technology Roadmap for Semiconductors (public.itrs.net), a definitive document for the electronics industry, now recognises that conventional 'top-down' technologies may have a limited remaining lifespan. It advocates a search for next generation technologies, recognising that molecular scale computation is an exceptionally promising prospect. It further highlights quantum information processing (QIP), the technology that would result from manipulating coherent superpositions of states, as having immense potential for certain applications. The research we describe here aims to create prototype elements for technologies of those classes.Project IMPRESS is concerned with the electron spin states within individual nanostructures, specifically carbon nanotube 'peapods'. Through a variety of characterisation techniques, and pioneering synthetic chemistry, we will develop the ability to engineer spin-spin interactions along a one-dimensional chain of intra-tube spins. Recent high-profile theoretical studies have shown that such a spin chain would have highly remarkable properties. It would be capable of rapidly transferring the spin states, i.e. the information, along the chain purely by virtue of the spin-spin interactions without any externally applied voltage or power dissipation. Moreover it is even possible to generate multi-spin entanglement, the underlying resource for QIP, purely through the free evolution of such a chain. Thus a molecular device of this kind could constitute a key building block for any technology based on information processing with electron spins, especially QIP.