近日，东北师范大学的衣学喜及其研究团队取得一项新进展。经过不懈努力，他们揭示耦合量子比特的老化现象。相关研究成果已于2024年7月18日在国际知名学术期刊《物理评论A》上发表。
在本文中，研究人员探讨了耦合量子比特网络中的老化跃迁。该研究的模型描述了由激光驱动的大量量子比特，具有耗散和相干量子比特-量子比特耦合。非活跃量子比特与总量子比特的比值以及处于激发态的量子比特的数量被用来表征老化跃迁。当比值超过一个阈值时，激发态的布居数突然下降，此时，研究人员发现一个跃迁。
这种行为很有趣，与耦合振荡器相反，耦合振荡器没有观察到突然下降。此外，研究人员还演示了耦合和驱动激光对阈值的影响。突然下降的基本物理原理得到了阐明。根据稳定性分析理论研究人员确定了老化跃迁发生的区域。
据悉，在经典物理学中，老化跃迁是指由于某些形式的退化而从振荡状态转变为全局停止状态。在量子振荡器中也观察到类似的行为。虽然它在耦合振荡器系统中得到了广泛的关注，但尚未在耦合量子比特中进行研究。
附：英文原文
Title: Aging of coupled qubits
Author: Huining Zhang, Dianzhen Cui, W. Wang, X. X. Yi
Issue&Volume: 2024/07/18
Abstract: The aging transition refers to the shift from an oscillatory state to a globally stopped state due to some forms of deterioration in classical physics. Similar behavior has also been observed in quantum oscillators. Although it has received extensive attention in coupled-oscillator systems, it has not yet been studied in coupled qubits. In this paper, we explore the aging transition in a network of coupled qubits. Our model describes numerous qubits driven by a laser, with both dissipative and coherent qubit-qubit couplings. The ratio of inactive qubits to total qubits and the population in the excited state of the qubits are employed to characterize the aging transition. We find a transition where the population in the excited states suddenly drops when the ratio exceeds a threshold. This behavior is intriguing and contrasts with coupled oscillators, for which no sudden drop is observed. Additionally, we demonstrate how the couplings and driving laser influence the threshold. The underlying physics of the sudden drop is elucidated. The region where the aging transition occurs is determined based on stability-analysis theory.
DOI: 10.1103/PhysRevA.110.012221
Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.110.012221
来源：小柯机器人