  Keyphrase extraction (KPE) is an important task in Natural Language
Processing for many scenarios, which aims to extract keyphrases that are
present in a given document. Many existing supervised methods treat KPE as
sequential labeling, span-level classification, or generative tasks. However,
these methods lack the ability to utilize keyphrase information, which may
result in biased results. In this study, we propose Diff-KPE, which leverages
the supervised Variational Information Bottleneck (VIB) to guide the text
diffusion process for generating enhanced keyphrase representations. Diff-KPE
first generates the desired keyphrase embeddings conditioned on the entire
document and then injects the generated keyphrase embeddings into each phrase
representation. A ranking network and VIB are then optimized together with rank
loss and classification loss, respectively. This design of Diff-KPE allows us
to rank each candidate phrase by utilizing both the information of keyphrases
and the document. Experiments show that Diff-KPE outperforms existing KPE
methods on a large open domain keyphrase extraction benchmark, OpenKP, and a
scientific domain dataset, KP20K.
