Engineered non-Hermitian systems featuring exceptional points (EPs) can lead to a host of extraordinary phenomena in diverse fields ranging from photonics, acoustics, opto-mechanics, and electronics to atomic physics. In optics, non-Hermitian dynamics are typically realized using dissipation and phase-insensitive gain accompanied by unavoidable fluctuations. Here, we introduce non-Hermitian dynamics of coupled optical parametric oscillators (OPOs) arising from phase-sensitive amplification and de-amplification, and show their distinct advantages over conventional non-Hermitian systems relying on laser gain and loss. OPO-based non-Hermitian systems can benefit from the instantaneous nature of the parametric gain, noiseless phase-sensitive amplification, and rich quantum and classical nonlinear dynamics. We show that two coupled OPOs can exhibit spectral anti-parity-time (anti-PT) symmetry and a EP between its degenerate and nondegenerate operation regimes. To demonstrate the distinct potentials of the coupled OPO system compared to conventional non-Hermitian systems, we present higher-order EPs with two OPOs, tunable Floquet EPs in a reconfigurable dynamic non-Hermitian system, and the generation of a squeezed vacuum around EPs, all of which are not easy to realize in other non-Hermitian platforms. We believe our results show that coupled OPOs are an outstanding non-Hermitian setting with unprecedented opportunities to realize nonlinear dynamical systems for enhanced sensing and quantum information processing.

中文翻译：

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耦合光学参量振荡器的非耗散非赫米特动力学和例外点

具有非凡点（EP）的非厄米工程系统可以在从光子学，声学，光机械学，电子学到原子物理学的各个领域导致一系列非同寻常的现象。在光学中，通常使用耗散和对相位不敏感的增益以及不可避免的波动来实现非赫米特动力学。在这里，我们介绍由相敏放大和去放大引起的耦合光学参量振荡器（OPO）的非赫米特动力学，并展示它们相对于依赖激光增益和损耗的常规非赫米特系统的独特优势。基于OPO的非Hermitian系统可以受益于参数增益的瞬时特性，无噪声的相敏放大以及丰富的量子和经典非线性动力学。我们表明，两个耦合的OPO可以展现光谱的反奇偶时间（anti-PT）对称性和简并的和非简并的操作方案之间的EP。为了证明与传统的非Hermitian系统相比，耦合OPO系统的独特潜力，我们提出了带有两个OPO的高阶EP，可重构动态非Hermitian系统中的可调Floquet EP，以及EP周围压缩真空的产生，所有这些都不容易在其他非Hermitian平台上实现。我们相信我们的结果表明，耦合的OPO是出色的非Hermitian环境，具有实现增强的传感和量子信息处理的非线性动力学系统的空前机会。为了证明与传统的非Hermitian系统相比，耦合OPO系统的独特潜力，我们提出了带有两个OPO的高阶EP，可重构动态非Hermitian系统中的可调Floquet EP，以及EP周围压缩真空的产生，所有这些都不容易在其他非Hermitian平台上实现。我们相信我们的结果表明，耦合的OPO是出色的非Hermitian设置，具有实现增强的传感和量子信息处理的非线性动力学系统的空前机会。为了证明与传统的非Hermitian系统相比，耦合OPO系统的独特潜力，我们提出了带有两个OPO的高阶EP，可重构动态非Hermitian系统中的可调Floquet EP，以及EP周围压缩真空的产生，所有这些都不容易在其他非Hermitian平台上实现。我们相信我们的结果表明，耦合的OPO是出色的非Hermitian环境，具有实现增强的传感和量子信息处理的非线性动力学系统的空前机会。所有这些都不容易在其他非Hermitian平台上实现。我们相信我们的结果表明，耦合的OPO是出色的非Hermitian环境，具有实现增强的传感和量子信息处理的非线性动力学系统的空前机会。所有这些都不容易在其他非Hermitian平台上实现。我们相信我们的结果表明，耦合的OPO是出色的非Hermitian环境，具有实现增强的传感和量子信息处理的非线性动力学系统的空前机会。