近日，兰州大学的安钧鸿教授及其研究小组取得一项新进展。经过不懈努力，他们通过量子态扩散方法探究了量子速度极限。相关研究成果已于2023年7月10日在国际知名学术期刊《物理评论A》上发表。

该研究团队提出了一种新的方法，通过量子态扩散方法从整个系统的角度来推导量子速度极限(QSL)的界限，与以往从开放系统的约化动力学中推导出QSL的方案不同。研究人员考虑了由开放系统和其环境组成的整个系统，并应用于两能级系统。研究结果表明，在无噪声情况下，该系统具有无限的加速能力，但这种能力在玻恩-马尔可夫近似下被环境所破坏。

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然而，在非马尔可夫动力学中，只要整个系统的能谱中存在束缚态，这种加速能力将在无噪声情况下恢复。这一研究成果丰富了对QSL的表征方法，并为控制开放系统的QSL提供了一种有效的途径。

据悉，量子速度极限（QSL）作为量子技术中的一个重要演化特征，在量子技术中具有关键作用。如何将已有的QSL从封闭系统推广到开放系统，已引起广泛关注。

附：英文原文

Title: Quantum speed limit from a quantum-state-diffusion method

Author: Wei Wu, Jun-Hong An

Issue&Volume: 2023/07/10

Abstract: Characterizing the most efficient evolution, the quantum speed limit (QSL) plays a significant role in quantum technology. How to generalize the well-established QSL from closed systems to open systems has attracted much attention. In contrast to the previous schemes to derive the QSL from the reduced dynamics of open systems, we propose a QSL bound from the point of view of the total system consisting of the open system and its environment using a quantum-state-diffusion method. The application of our scheme to a two-level system reveals that the system possesses an infinite speedup capacity in the noiseless case, which is destroyed by the environment under the Born-Markovian approximation. It is interesting to find that the capacity in the noiseless case is recovered in the non-Markovian dynamics as long as a bound state is formed in the energy spectrum of the total system. Enriching the characterization schemes of the QSL, our result provides an efficient way to control the QSL of open systems.

DOI: 10.1103/PhysRevA.108.012204

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.108.012204

来源：科学网 小柯机器人