Quantum correlations and entanglement shared among multiple quantum beams are important for both fundamental science and the development of quantum technologies. The enhancement for them is necessary and important to implement the specific quantum tasks and goals. Here, we report a correlation injection scheme (CIS) which is an effective method to enhance the quantum correlations and entanglement in the symmetrical cascaded four-wave mixing processes, and the properties of quantum correlations and entanglement can be characterized by the values of the degree of intensity-difference squeezing (DS) and the smallest symplectic eigenvalues, respectively. Our results show that the CIS can enhance the quantum correlations and entanglement under certain conditions, while for other conditions it can only decrease the values of the DS and the smallest symplectic eigenvalues to the level of standard quantum limit, respectively. We believe that our scheme is experimentally accessible and will contribute to a deeper understanding of the manipulations of the quantum correlations and entanglement in various quantum networks.

中文翻译：

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级联四波混频过程中使用相关注入方案增强量子相关性

多个量子束之间共享的量子相关性和纠缠对于基础科学和量子技术的发展都很重要。对它们的增强对于实现特定的量子任务和目标是必要且重要的。在这里，我们报道了一种相关注入方案（CIS），它是增强对称级联四波混频过程中量子相关性和纠缠度的有效方法，并且可以通过度值来表征量子相关性和纠缠度的性质。强度差压缩（DS）和最小辛特征值。我们的结果表明，CIS在某些条件下可以增强量子相关性和纠缠，对于其他条件，只能将DS的值和最小辛特征值分别减小到标准量子极限的水平。我们相信我们的方案在实验上是可访问的，并且将有助于更深入地理解各种量子网络中的量子相关性和纠缠的操纵。