The Bell basis is a distinctive set of maximally entangled two-particle quantum states that forms the foundation for many quantum protocols such as teleportation, dense coding, and entanglement swapping. While the generation, manipulation, and measurement of two-level quantum states are well understood, the same is not true in higher dimensions. Here we present the experimental generation of a complete set of Bell states in a four-dimensional Hilbert space, comprising 16 orthogonal entangled Bell-like states encoded in the orbital angular momentum of photons. The states are created by the application of generalized high-dimensional Pauli gates on an initial entangled state. Our results pave the way for the application of high-dimensional quantum states in complex quantum protocols such as quantum dense coding.

中文翻译：

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生成完整的四维Bell基础

贝尔的基础是最大纠缠的两个粒子量子态的独特集合，这为许多量子协议（例如，隐形传态，密集编码和纠缠交换）奠定了基础。尽管人们对二级量子态的产生，操纵和测量已广为人知，但在更高维度上却并非如此。在这里，我们介绍了在四维希尔伯特空间中一组完整的Bell状态的实验生成，包括在光子的轨道角动量中编码的16个正交纠缠的Bell类状态。通过在初始纠缠态上应用广义高维Pauli门来创建状态。我们的结果为高维量子态在复杂量子协议（例如量子密集编码）中的应用铺平了道路。