近日，东北师范大学量子科学中心的沈宏志&衣学喜及其研究团队取得一项新进展。经过不懈努力，他们揭示了驱动耗散耦合腔中具有非马尔可夫效应的非常规光子封锁现象。相关研究成果已于2024年4月29日在国际知名学术期刊《物理评论A》上发表。

本文构建了一个非马尔可夫效应的耦合腔系统，其中左腔无耗散，右腔有马尔可夫耗散，分别由双光子泵浦和单光子驱动场介导。通过真空状态下环境初始化的马尔可夫主方程和海森堡-朗之万方程的等价性，可以导出包含双光子泵浦和有效单光子驱动场的左腔精确的非马尔可夫海森堡-朗之万方程和简化的主方程。在非马尔可夫状态下(耗散低于阈值)，有效单光子驱动场保持非零，这可能导致由于封闭量子干涉路径形成而导致UPB发生。

当耗散超过阈值时，系统进入马尔可夫状态，此时UPB减弱。特别是当耗散接近无穷大时，由于有效单光子驱动场趋于零，左腔的UPB消失。研究人员成功解析并导出了UPB的最优条件，与数值模拟结果高度吻合。他们还深入探讨了两个腔均存在耗散的情况。进一步地，将这一模型推广至包含无耗散左腔（由双光子泵驱动）与非相互作用的耗散右腔（由单光子驱动场驱动）耦合的普遍系统。这项研究方案可能为非马尔可夫效应在光子统计和量子光学中的应用铺平道路。

据悉，基于破坏性量子干涉的光子封锁被称为非常规光子封锁(UPB)，它在马尔可夫系统中得到了广泛的研究，但在非马尔可夫系统中却很少被探索。

附：英文原文

Title: Unconventional photon blockade with non-Markovian effects in driven dissipative coupled cavities

Author: H. Z. Shen, J. F. Yang, X. X. Yi

Issue&Volume: 2024/04/29

Abstract: The photon blockade based on destructive quantum interference is called the unconventional photon blockade (UPB), which has been intensively studied in Markovian systems but barely explored in the non-Markovian ones. In this paper, we construct a coupled-cavities system to achieve UPB with the non-Markovian effect, where the dissipationless left cavity and Markovian dissipative right cavity are respectively mediated by two-photon pump and single-photon driving field. Through the equivalence between the Markovian master equation and Heisenberg-Langevin equation for the environment initialization in the vacuum state, we can derive the exact non-Markovian Heisenberg-Langevin equation and reduced master equation for the left cavity, which contains the two-photon pump and effective single-photon driving field. In the non-Markovian regime (the dissipation falling below a threshold), the effective single-photon driving field holds nonzero, which can lead to UPB occurring due to a closed quantum interference path forming. When the dissipation exceeds the threshold, the system enters the Markovian regime, where UPB weakens. Especially, if the dissipation approaches infinity, UPB for the left cavity disappears due to the effective single-photon driving field tending to zero. We analytically derive an optimal condition for UPB, which is in good agreement with that obtained by the numerical simulation. We also discuss the situation where both cavities have dissipations. Finally, the above model is extended to a general system involving a dissipationless left cavity (mediated by two-photon pump) coupling with noninteracting dissipative right cavities (driven by single-photon driving fields). Our scheme might pave an avenue towards applications on photon statistics and quantum optics with the non-Markovian effect.

DOI: 10.1103/PhysRevA.109.043714

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.109.043714