  Often questions provided to open-domain question answering systems are
ambiguous. Traditional QA systems that provide a single answer are incapable of
answering ambiguous questions since the question may be interpreted in several
ways and may have multiple distinct answers. In this paper, we address
multi-answer retrieval which entails retrieving passages that can capture
majority of the diverse answers to the question. We propose a re-ranking based
approach using Determinantal point processes utilizing BERT as kernels. Our
method jointly considers query-passage relevance and passage-passage
correlation to retrieve passages that are both query-relevant and diverse.
Results demonstrate that our re-ranking technique outperforms state-of-the-art
method on the AmbigQA dataset.
