REIGN: Refurbished Embeddings with Integrated Guidance Networks for Efficient Context-Length Scaling

Devrim Çavuşoğlu, Emre Akbas


Abstract
Dense retrieval over long documents is expensive. Token-level encoders scale quadratically in sequence length, and most long-context embedding models reach 32K tokens only through architectural workarounds or by stretching billion-parameter LLMs. We propose REIGN (Refurbished Embeddings with Integrated Guidance Networks), a contrastively trained bi-encoder that operates on sequences of contextualised chunk embeddings from a frozen Guidance Network (GN) rather than on raw tokens. REIGN targets multi-chunk inputs and primarily document-to-document retrieval; single-chunk inputs stay with the GN. Decoupling token-level processing from document-level reasoning, and caching the GN embeddings to disk, cuts per-document training cost by roughly four orders of magnitude relative to chunked Transformer fine-tuning. We also release a synthetic long-document retrieval benchmark for contrastive training and evaluation at long context lengths. Across an in-distribution Wikipedia benchmark, the LoCo out-of-distribution suite, and a real-world patent retrieval case study, REIGN matches dense long-context retrievers at smaller parameter budgets per regime. A paired significance test puts it on par with models 1.6–4.3× larger on the patent task, and it stays within 0.65 nDCG@10 of a 20×-larger model on LoCo.
Anthology ID:
2026.findings-emnlp.1487
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
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
31659–31677
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URL:
https://aclanthology.org/2026.findings-emnlp.1487/
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Cite (ACL):
Devrim Çavuşoğlu and Emre Akbas. 2026. REIGN: Refurbished Embeddings with Integrated Guidance Networks for Efficient Context-Length Scaling. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 31659–31677, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
REIGN: Refurbished Embeddings with Integrated Guidance Networks for Efficient Context-Length Scaling (Çavuşoğlu & Akbas, Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.1487.pdf