Exploring coherent dynamics and field clocking of quantum-dot cellular automata circuits

硅技术和计算机设计工具的进步使拥有超过10亿个晶体管的芯片得以生产。然而，很明显，为了推动扩展的最终极限，需要根本不同的想法。由于工业界和政府的投资，在纳米和原子尺度上以令人难以置信的精度操纵物质的技术是可行的，这使我们可以考虑将分子和原子器件作为传统晶体管的潜在接班人。量子点元胞自动机（QCA）是一种基于双稳定分子和原子纳米结构动态阵列的场相互作用的计算范式，已被证明可以实现通用计算，并有助于显着降低功耗，这是缩放传统技术的主要挑战。最近令人兴奋的实验展示了在原子尺度上的功能QCA装置，提供了强有力的证据，证明QCA确实可以达到尺度的最终极限。

Advancements in silicon technology and the computer design tools have enabled the production of chips that have over a billion transistors. However, it has become clear that fundamentally different ideas are necessary in order to push the ultimate limits of scaling. As a result of the investment by both industry and governments, technology is available for manipulating matter at the nano and atomic scale with incredible precision allowing us to consider molecular and atomic devices as potential successors to the conventional transistor. Quantum-dot cellular automata (QCA), a computing paradigm based on the field interaction of dynamic arrays of bi-stable molecular and atomic nanostructures has been shown to implement general purpose computing, as well as contribute to significant reductions in power dissipation, a major challenge with scaling conventional technology. Exciting recent experiments demonstrated a functional QCA device at the atomic scale, providing strong evidence that QCA can indeed reach the ultimate limits of scaling. QCADesigner, the most widely used numerical simulation tool for QCA research has enabled a large number of fundamental circuit and system level studies of this emerging technology. Analytical and numerical research using this tool has highlighted the critical issue of coherent dynamics in QCA and its impact on the ability of the numerical tools to identify the correct system ground state for an arbitrary layout and input vector. The purpose of this fundamental research is to provide entirely new theoretical and numerical tools for QCA by developing and integrating a model for coherent dynamics and the necessary tools to simulate field clocked molecular QCA arrays. These tools will enable a broad range of fundamentally new research studies of the behaviour of QCA circuits and systems including critical studies of the effect of coherent dynamics on the clocking networks, power dissipation, circuit density, and the potential of QCA as a scalable quantum computing technology. These studies will facilitate an improved assessment of the commercial potential of QCA even before all the technical challenges associated with its implementation are fully solved.