Grover's algorithm, a well-know quantum search algorithm, allows one to find the correct item in a database, with quadratic speedup. In this paper we adapt Grover's algorithm to the problem of finding a correct answer to a natural language question in English, thus contributing to the growing field of Quantum Natural Language Processing. Using a grammar that can be interpreted as tensor contractions, each word is represented as a quantum state that serves as input to the quantum circuit. We here introduce a quantum measurement to contract the representations of words, resulting in the representation of larger text fragments. Using this framework, a representation for the question is found that contains all the possible answers in equal quantum superposition, and allows for the building of an oracle that can detect a correct answer, being agnostic to the specific question. Furthermore, we show that our construction can deal with certain types of ambiguous phrases by keeping the various different meanings in quantum superposition.

中文翻译：

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Grover 的问答算法

Grover 算法是一种众所周知的量子搜索算法，它允许人们以二次加速的方式在数据库中找到正确的项目。在本文中，我们将 Grover 算法应用于寻找英语自然语言问题的正确答案的问题，从而为不断发展的量子自然语言处理领域做出贡献。使用可以解释为张量收缩的语法，每个单词都表示为一个量子状态，作为量子电路的输入。我们在这里引入了一种量子测量来收缩单词的表示，从而产生更大的文本片段的表示。使用这个框架，可以找到问题的一个表示，它包含所有可能的相等量子叠加的答案，并允许构建一个可以检测正确答案的预言机，对具体问题不可知。此外，我们表明我们的构造可以通过在量子叠加中保留各种不同的含义来处理某些类型的歧义短语。