近日，法国勃艮第大学（UBFC）的J. Lages与法国巴黎萨克雷大学的A. D. Chepelianskii合作，成功增强了两个振荡器之间的量子交换。相关研究成果已于2023年4月13日在国际学术期刊《物理评论A》上发表。

该研究团队探讨了两个量子振子如何通过一个三能级系统（可以是固体中着色中心的自旋能级）高效地交换它们的量子态。研究人员利用哈密顿工程和量子控制技术获得了高转移概率。从弱耦合近似开始，研究人员推导出自旋-振子相互作用哈密顿量的条件，从而实现高保真度的量子交换。他们发现这些条件不能对任意自旋-振子耦合满足。

为了克服这个限制，他们演示了如何通过施加于三能级系统的时变控制场来实现所需的激发交换的有效动力学。在（超）强耦合区域，由于激发分散到振子的许多福克态上，会导致重要的保真度损失。他们展示了通过优化控制数值算法计算出的适当控制场，可以显著减少这种不利影响。

附：英文原文

Title: Enhancing quantum exchanges between two oscillators

Author: Q. Ansel, A. D. Chepelianskii, J. Lages

Issue&Volume: 2023/04/13

Abstract: We explore the extent to which two quantum oscillators can exchange their quantum states efficiently through a three-level system which can be spin levels of colored centers in solids. High transition probabilities are obtained using Hamiltonian engineering and quantum control techniques. Starting from a weak-coupling approximation, we derive conditions on the spin-oscillator interaction Hamiltonian that enable a high-fidelity exchange of quanta. We find that these conditions cannot be fulfilled for arbitrary spin-oscillator coupling. To overcome this limitation, we illustrate how a time-dependent control field applied to the three-level system can lead to an effective dynamic that performs the desired exchange of excitation. In the (ultra)strong-coupling regime, an important loss of fidelity is induced by the dispersion of the excitation onto many Fock states of the oscillators. We show that this detrimental effect can be substantially reduced by suitable control fields, which are computed with optimal control numerical algorithms.

DOI: 10.1103/PhysRevA.107.042609

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.107.042609