模拟监测引起的小系统拓扑相变
近日，浙江理工大学陈爱喜团队发现了模拟监测引起的小系统拓扑相变。相关论文于2025年8月18日发表在《物理评论A》杂志上。
开放量子点阵系统的拓扑性质由于其重要的基础意义和潜在的应用前景而备受关注。然而，大规模晶格模型的实验证明仍然具有挑战性。最重要的是，根据量子轨迹的拓扑公式需要监测量子跳跃。这对于依赖于跳跃时间平均量子轨迹的暗态诱导拓扑来说尤其如此。
研究组提出了两个重要的简化，以减轻实验负担，以证明暗状态诱导的拓扑相变：首先，他们在小系统的相空间中模拟拓扑，其中系统的有效尺寸由可访问的参数范围反映。其次，开发了一种方法，通过一个辅助系统来改善，通过标准的时间平均来获得跳跃时间平均状态，有效地替代了量子跳跃的监测和计数。虽然这些简化适用于一般晶格系统，但该团队用一维Su-Schrieeffer-Heeger模型来证明它们。在这种情况下，晶格系统由一个四能级系统模拟，而跳跃时间平均状态直到第二次跳跃通过一个三能级辅助系统访问。
附：英文原文
Title: Simulating monitoring-induced topological phase transitions with small systems
Author: Rui Xie, Clemens Gneiting, Zheng-Yang Zhou, Ai-Xi Chen
Issue&Volume: 2025/08/18
Abstract: The topological properties of open quantum lattice systems have attracted much attention, due to their fundamental significance and potential applications. However, experimental demonstrations with large-scale lattice models remain challenging. On top of that, formulations of topology in terms of quantum trajectories require monitoring along with the detection of quantum jumps. This is particularly the case for the dark-state-induced topology that relies on averaging quantum trajectories at their jump times. Here we propose two significant simplifications to ease the experimental burden to demonstrate dark state-induced topological phase transitions: First, we emulate the topology in the phase space of small systems, where the effective size of the system is reflected by the accessible parameter range. Second, we develop a method how to, by augmenting the system with an auxiliary system, access the jump-time-averaged state through standard wall-time averaging, which effectively substitutes the monitoring along with the counting of quantum jumps. While these simplifications are applicable to general lattice systems, we demonstrate them with a one-dimensional Su-Schrieeffer-Heeger model. In this case, the lattice system is emulated by a four-level system, while the jump-time-averaged state up to the second jump is accessed through a three-level auxiliary system.
DOI: 10.1103/yk7m-hcqr
Source: https://journals.aps.org/pra/abstract/10.1103/yk7m-hcqr
来源：科学网 小柯机器人
