论文标题
通过量子幻灯片通过量子步行计算量子计算
Quantum Computing by Quantum Walk on Quantum Slide
论文作者
论文摘要
连续时量子步行是量子计算的替代方法之一，可以通过将量子步行器散射在嵌入稀疏图中的一些特殊设计的结构上[Childs，physs，phys。莱特牧师。 2009]。飞秒激光铭刻的光学波导的最新进展代表了实现这种量子步行模型的有希望的物理平台。但是，主要的挑战是准备平面波初始状态的问题。以前，已经提出了量子幻灯片的概念，并实现了用于证明NAND树的工作原理的实验[Wang等。 PHY。莱特牧师。 2020]。在这里，我们展示了如何进一步应用量子幻灯片以实现通用量子计算，并绕过了平面波的需求。具体而言，我们将外部磁场应用于完美的状态转移链，该链可以生成具有任意动量的移动高斯波数据包。当正确调整阶段时，可以在我们的计划中实现Childs提案中的通用门设置。此外，我们表明，栅极的忠诚度随幻灯片的长度而增加，并且可以渐近地达到统一。
Continuous-time quantum walk is one of the alternative approaches to quantum computation, where a universal set of quantum gates can be achieved by scattering a quantum walker on some specially-designed structures embedded in a sparse graph [Childs, Phys. Rev. Lett. 2009]. Recent advances in femtosecond laser-inscribed optical waveguides represent a promising physical platform for realizing this quantum-walk model of quantum computation. However, the major challenge is the problem of preparing a plane-wave initial state. Previously, the idea of quantum slide has been proposed and experimentally realized for demonstrating the working principle of NAND tree [Wang et al. Phy. Rev. Lett. 2020]. Here we show how quantum slide can be further applied to realize universal quantum computation, bypassing the plane-wave requirement. Specifically, we apply an external field to the perfect-state-transfer chain, which can generate a moving Gaussian wave packet with an arbitrary momentum. When the phase is properly tuned, the universal gate set in Childs' proposal can be realized in our scheme. Furthermore, we show that the gate fidelities increase with the length of the slide, and can reach unity asymptotically.
