We show that for pure and mixed states the problem of maximizing the correlation measure in the Clauser-Horne-Shimony-Holt inequality reduces to maximizing the perimeter of a parallelogram enclosed by an ellipse characterized by the entanglement contained in the bipartite system. Our geometrical description is valid for a nonmaximally entangled state. We also determine the corresponding optimal measurements.

中文翻译：

---

非最大纠缠态的 Clauser-Horne-Shimony-Holt 不等式的几何解释

我们表明，对于纯态和混合态，最大化 Clauser-Horne-Shimony-Holt 不等式中的相关度量的问题简化为最大化由椭圆包围的平行四边形的周长，该椭圆以二分系统中包含的纠缠为特征。我们的几何描述适用于非最大纠缠态。我们还确定了相应的最佳测量值。