"Query expansion"[0] has been an information retrieval technique for a while, but using LLMs to help with query expansion is fairly new and promising, e.g. "Query Expansion by Prompting Large Language Models"[1], and "Query2doc: Query Expansion with Large Language Models"[2].
[0] https://en.wikipedia.org/wiki/Query_expansion
[1] https://arxiv.org/abs/2305.03653
[2] https://arxiv.org/abs/2303.07678
