Atom-RAG: Atomic Fact-Centric Retrieval for Multi-Hop Reasoning

Seok Jun Hwang, Soohyeong Kim, JungHyoun Kim, Jeonghyeon Park, Yong Suk Choi


Abstract
Retrieval-Augmented Generation (RAG) en- hances large language models with ex- ternal knowledge but often suffers from query–evidence mismatch due to inappropriate retrieval granularity. Chunk-level retrieval can introduce substantial noise, while graph-based retrieval may suffer from overly fine-grained or densely connected structures that hinder effec- tive multi-hop reasoning. To address this issue, we propose Atom-RAG, a retrieval-augmented framework based on atomic fact–centric knowl- edge representation and granularity-aligned re- trieval. Atom-RAG represents documents as collections of atomic facts and aligns retrieval with the fine-grained information needs of com- plex queries. By decomposing queries into fact-level subqueries, the framework retrieves and aggregates evidence in a manner aligned with the information requirements of multi-hop reasoning, producing a compact and evidence- aligned context for generation. Experiments on benchmarks covering different reasoning depths show that Atom-RAG consistently out- performs strong iterative and graph-based RAG baselines, achieving improved multi-hop QA performance and stronger evidence retrieval. These results highlight the importance of align- ing the granularity of queries and retrieval units for reliable multi-hop reasoning within a unified retrieval pipeline. Code and data are available at https://github.com/cody628/ AtomRAG.
Anthology ID:
2026.findings-emnlp.2323
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
49872–49890
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2323/
DOI:
10.18653/2026.findings-emnlp.2323
Bibkey:
Cite (ACL):
Seok Jun Hwang, Soohyeong Kim, JungHyoun Kim, Jeonghyeon Park, and Yong Suk Choi. 2026. Atom-RAG: Atomic Fact-Centric Retrieval for Multi-Hop Reasoning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 49872–49890, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Atom-RAG: Atomic Fact-Centric Retrieval for Multi-Hop Reasoning (Hwang et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.2323.pdf