Demonstration of Quantum Brachistochrones between Distant States of an Atom
Demonstration of Quantum Brachistochrones between Distant States of an Atom
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DOI：
10.1103/physrevx.11.011035
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发表时间：
2021-02-19
影响因子：
12.5
通讯作者：
Alberti, Andrea
中科院分区：
文献类型：
--
作者：
Lam, Manolo R.;Peter, Natalie;Alberti, Andrea
对于许多基于量子力学的技术来说，通过尽可能快的路径-量子腕钟-将初始量子态转换为目标态是一个根本性的挑战。在二能级系统中，量子臂时子解早已为人所知。然而，这些解决方案不适用于较大的系统，特别是当无法通过本地转换达到目标状态时。在这里，我们演示了原子波包在15倍于其大小的距离上的快速相干传输--这是一个超越二能级系统的量子过程的范例。我们对输运保真度的测量表明，物质波的相干分裂和复合存在一个最小持续时间--量子速度极限。我们通过依赖量子态动力学的几何解释来获得对这一极限的物理洞察。这些结果揭示了量子态动力学的基本极限，并有望在量子传感和量子计算中找到相关应用。
Transforming an initial quantum state into a target state through the fastest possible route-a quantum brachistochrone-is a fundamental challenge for many technologies based on quantum mechanics. In two-level systems, the quantum brachistochrone solutions are long known. These solutions, however, are not applicable to larger systems, especially when the target state cannot be reached through a local transformation. Here, we demonstrate fast coherent transport of an atomic wave packet over a distance of 15 times its size-a paradigmatic case of quantum processes going beyond the two-level system. Our measurements of the transport fidelity reveal the existence of a minimum duration-a quantum speed limit-for the coherent splitting and recombination of matter waves. We obtain physical insight into this limit by relying on a geometric interpretation of quantum state dynamics. These results shed light on a fundamental limit of quantum state dynamics and are expected to find relevant applications in quantum sensing and quantum computing.