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arXiv 1111.1579quant-phcond-mat.soft
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高保真量子驱动

High-fidelity quantum driving

Mark G. Bason, Matthieu Viteau, Nicola Malossi, Paul Huillery, Ennio Arimondo, Donatella Ciampini, Rosario Fazio, Vittorio Giovannetti, Riccardo Mannella, Oliver Morsch

摘要:

精确控制量子系统的能力是现代科学许多领域的基本要求,例如量子信息处理和分子系统的相干操纵。通常需要在尽可能短的时间内实现这些量子操纵,以使退相干最小化,并且具有对控制参数波动的大的稳定性。虽然针对速度优化协议导致以植根于海森堡不确定原理的量子速度极限的形式的自然下限,但是针对参数变化的稳定性通常需要系统的绝热跟随。量子控制的最终目标是以100%的保真度制备所需的状态。在这里,我们实验实现了最佳的控制方案,实现了接近完美的保真度的二能级量子系统实现玻色-爱因斯坦凝聚体在光晶格。通过适当地调整系统参数的时间依赖性,我们通过一个捷径协议将初始量子态转换为所需的最终状态,达到与量子力学定律兼容的最大速度。在相反的限制,我们实现了最近提出的无跃迁超绝热协议,其中系统完全遵循瞬时绝热基态。我们表明,超绝热协议是非常强大的参数变化,使他们在实际应用中很有用。

英文摘要:

The ability to accurately control a quantum system is a fundamental requirement in many areas of modern science such as quantum information processing and the coherent manipulation of molecular systems. It is usually necessary to realize these quantum manipulations in the shortest possible time in order to minimize decoherence, and with a large stability against fluctuations of the control parameters. While optimizing a protocol for speed leads to a natural lower bound in the form of the quantum speed limit rooted in the Heisenberg uncertainty principle, stability against parameter variations typically requires adiabatic following of the system. The ultimate goal in quantum control is to prepare a desired state with 100% fidelity. Here we experimentally implement optimal control schemes that achieve nearly perfect fidelity for a two-level quantum system realized with Bose-Einstein condensates in optical lattices. By suitably tailoring the time-dependence of the system's parameters, we transform an initial quantum state into a desired final state through a short-cut protocol reaching the maximum speed compatible with the laws of quantum mechanics. In the opposite limit we implement the recently proposed transitionless superadiabatic protocols, in which the system perfectly follows the instantaneous adiabatic ground state. We demonstrate that superadiabatic protocols are extremely robust against parameter variations, making them useful for practical applications.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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