Mastodawn

🚨 Introducing 𝗚𝗿𝗶𝘁𝗛𝗼𝗽𝗽𝗲𝗿, the new State-of-the-Art Multi-Hop Dense Retriever 🦗

Current approaches to multi-hop retrieval face critical trade-offs.

🔎 Decomposition-based methods break complex queries into simpler steps, but they are computationally expensive and difficult to train end-to-end.

⚡ Decomposition-free methods improve efficiency, but often struggle with long reasoning chains and generalization beyond their training data.

So how can we get the best of both worlds?

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UKP Lab

💡 𝗚𝗿𝗶𝘁𝗛𝗼𝗽𝗽𝗲𝗿 is designed to deliver both efficiency and robustness, while enabling strong multi-hop reasoning without explicit decomposition.
🧩 𝗖𝗼𝗿𝗲 𝗶𝗱𝗲𝗮: unified learning for retrieval and reasoning

GritHopper’s joint training objective combines contrastive learning for embedding similarity with causal language modeling for next-token prediction.

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UKP Lab Mar 10

📌 𝗪𝗵𝗮𝘁 𝗺𝗮𝗸𝗲𝘀 𝗚𝗿𝗶𝘁𝗛𝗼𝗽𝗽𝗲𝗿 𝘀𝘁𝗮𝗻𝗱 𝗼𝘂𝘁?
✅ 𝗘𝗻𝗰𝗼𝗱𝗲𝗿-𝗼𝗻𝗹𝘆 𝗲𝗳𝗳𝗶𝗰𝗶𝗲𝗻𝗰𝘆: each hop requires just a single forward pass
🌍 𝗢𝘂𝘁-𝗼𝗳-𝗱𝗶𝘀𝘁𝗿𝗶𝗯𝘂𝘁𝗶𝗼𝗻 𝗿𝗼𝗯𝘂𝘀𝘁𝗻𝗲𝘀𝘀: stronger generalization than existing decomposition-free baselines
🔗 𝗨𝗻𝗶𝗳𝗶𝗲𝗱 𝘁𝗿𝗮𝗶𝗻𝗶𝗻𝗴: bridges dense retrieval and generative objectives, showing how post-retrieval generation loss improves retrieval
🧠 𝗦𝗲𝗹𝗳-𝘀𝘁𝗼𝗽𝗽𝗶𝗻𝗴 𝗿𝗲𝗮𝘀𝗼𝗻𝗶𝗻𝗴: uses generative capabilities inspired by ReAct to control its own state and determine when to stop

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UKP Lab Mar 10

📄 𝗚𝗥𝗜𝗧𝗛𝗼𝗽𝗽𝗲𝗿: 𝗗𝗲𝗰𝗼𝗺𝗽𝗼𝘀𝗶𝘁𝗶𝗼𝗻-𝗙𝗿𝗲𝗲 𝗠𝘂𝗹𝘁𝗶-𝗛𝗼𝗽 𝗗𝗲𝗻𝘀𝗲 𝗥𝗲𝘁𝗿𝗶𝗲𝘃𝗮𝗹
🌐 Project Website: https://ukplab.github.io/eacl2026-GritHopper/
🔗 Paper (arXiv): https://arxiv.org/pdf/2503.07519
🔗 Code: https://github.com/UKPLab/GritHopper
🔗 Model: https://huggingface.co/UKPLab/GritHopper-7B

GRITHopper: Decomposition-Free Multi-Hop Dense Retrieval

State-of-the-art multi-hop dense retrieval without query decomposition. Accepted at EACL 2026. Code, model & paper available.

GRITHopper

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UKP Lab Mar 10

👥 Justus-Jonas Erker (UKP Lab/Technische Universität Darmstadt), Nils Reimers (Cohere), Iryna Gurevych (UKP Lab/Technische Universität Darmstadt)

See you at Hashtag#EACL2026 in Rabat 🕌!

#UKPLab #NLP #NLProc #InformationRetrieval #DenseRetrieval #MultiHop #FactChecking #QuestionAnswering #RAG