IR 2 — Paper menu (choose your paper)

How to choose. Read the abstracts of the papers that interest you (the bidding page shows each one in full), then rank 3 to 5 of them there by Sept 30: name, email, whether you took the spring IR course, an optional preferred partner. Your bids must cover at least three different sessions, with at least two on Nov 13 or Nov 20; presenting early keeps December free for other exams. Bids are visible to everyone and can be changed until the deadline. On Nov 4 (postponed from Oct 5) pairs are formed (a newcomer with a returning student) and papers assigned to maximise everyone's preferences, one paper per pair; discussant roles are published the same day.

What you commit to. A 25-minute talk, a 10-minute live demo (three queries: hero, failure, wildcard), a reproduction of one key result at small scale, and a run of the method on the shared testbed: Track A (SciFact, NFCorpus, ArguAna and the scientific-article set, nDCG@10 with a p-value) for ranking papers, Track B (the 92k MS MARCO subset, queries per second, index size, RAM) for efficiency papers. See program §6 for the testbed, the compute guide and the contrastive-training starter notebook that papers marked training build on. You present once, with your partner, and you are discussant once for another pair's paper: you read it and their code, send them two questions in advance, and lead the dialogue in the session. Difficulty ★ = accessible, ★★ = solid work, ★★★ = ambitious; compute laptop / Colab / Colab + a few euros of API. The full annotated review with more detail per paper is full review.

Every paper below has public code or models unless stated. "Classic" = the reference everybody cites; "recent" = 2024–2026.


Session 2 (Nov 13) — Representations: how embeddings are trained, and where they break

1. SimCSE: Simple Contrastive Learning of Sentence Embeddings (Gao, Yao & Chen, EMNLP 2021) · classic · ★ · laptop/Colab · training

2. LLM2Vec: Large Language Models Are Secretly Powerful Text Encoders (BehnamGhader et al., COLM 2024) · recent · ★★ · Colab · training

3. Contextual Document Embeddings (Morris & Rush, ICLR 2025) · recent · ★★ · Colab · training

4. On the Theoretical Limitations of Embedding-Based Retrieval (LIMIT) (Weller et al., ICLR 2026) · recent · ★★ · laptop

5. SPLADE: Sparse Lexical and Expansion Model for First-Stage Ranking (Formal et al., SIGIR 2021; SPLADE-v3 2024) · classic · ★ · laptop/Colab · training · Track B

6. Timeline talk: static embeddings are back — Model2Vec and static retrieval models (Aarsen, HF blog 2025; Model2Vec 2024) · recent, non-peer-reviewed · ★ · laptop


Session 3 (Nov 20) — Domains: scientific papers, patents, adaptation, languages

7. SemCSE: Semantic Contrastive Sentence Embeddings Using LLM-Generated Summaries for Scientific Abstracts (Brinner & Zarriess, 2025) · recent · ★★ · Colab · training

8. PaECTER: Patent-Level Representation Learning Using Citation-Informed Transformers (Ghosh et al., 2024) · recent · ★★ · Colab · training

9. DAPFAM and PatenTEB: a patent retrieval benchmark and a patent embedding benchmark (Ayaou et al., 2025) · recent · ★★ · laptop/Colab

10. GPL: Generative Pseudo Labeling for Unsupervised Domain Adaptation of Dense Retrieval (Wang et al., NAACL 2022) · classic · ★ · Colab · training

11. BGE-M3: Multi-Linguality, Multi-Functionality, Multi-Granularity Text Embeddings (Chen et al., Findings of ACL 2024) · recent · ★★ · Colab

12. Timeline talk: Unsupervised word embeddings capture latent knowledge from materials science literature (Tshitoyan et al., Nature 2019) · classic · ★★ · laptop


Session 4 (Nov 27) — LLMs in the loop: rerankers, rewriters, reasoning

13. Is ChatGPT Good at Search? LLMs as Re-Ranking Agents (RankGPT) (Sun et al., EMNLP 2023) · classic · ★ · Colab (+ optional API)

14. Rank1: Test-Time Compute for Reranking (Weller et al., COLM 2025) · recent · ★★ · Colab

15. HyDE: Precise Zero-Shot Dense Retrieval without Relevance Labels (Gao et al., ACL 2023) · classic · ★ · laptop + small LLM

16. BRIGHT: A Realistic and Challenging Benchmark for Reasoning-Intensive Retrieval (Su et al., ICLR 2025) · recent · ★★ · Colab

17. Transformer Memory as a Differentiable Search Index (DSI) (Tay et al., NeurIPS 2022) · classic · ★★ · Colab · training

18. From RankNet to LambdaRank to LambdaMART (Burges, Microsoft Research 2010) · classic · ★ · laptop


Session 5 (Dec 4) — RAG and agents

19. Self-RAG: Learning to Retrieve, Generate, and Critique through Self-Reflection (Asai et al., ICLR 2024) · classic · ★★★ · Colab

20. RAPTOR: Recursive Abstractive Processing for Tree-Organized Retrieval (Sarthi et al., ICLR 2024) · recent · ★★ · Colab

21. Dense X Retrieval: What Retrieval Granularity Should We Use? (Chen et al., EMNLP 2024) · recent · ★ · laptop/Colab

22. The Power of Noise: Redefining Retrieval for RAG Systems (Cuconasu et al., SIGIR 2024) · recent · ★ · laptop/Colab

23. Search-R1: Training LLMs to Reason and Leverage Search Engines with Reinforcement Learning (Jin et al., 2025) · recent · ★★★ · Colab (inference)


Session 6 (Dec 11) — Trust: evaluation, attacks, bias, and documents that are not text

24. Can LLMs replace relevance assessors? Thomas et al. (SIGIR 2024) · UMBRELA (2024) · Clarke & Dietz (2024/26) · recent · ★★ · laptop/Colab

25. eRAG: Evaluating Retrieval Quality in Retrieval-Augmented Generation (Salemi & Zamani, SIGIR 2024) · recent · ★★ · Colab

26. PoisonedRAG: Knowledge Corruption Attacks to RAG of LLMs (Zou et al., USENIX Security 2025) · recent · ★★ · Colab

27. Neural Retrievers Are Biased Towards LLM-Generated Content (Dai et al., KDD 2024) · recent · ★ · laptop + small LLM

28. ColPali: Efficient Document Retrieval with Vision Language Models (Faysse et al., ICLR 2025) · recent · ★★ · Colab · own PDF testbed


Alternates (ask if you would rather present one of these)

MUVERA: multi-vector retrieval via fixed-dimensional encodings (NeurIPS 2024, a numpy project) · RaBitQ 1-bit quantisation with error bounds (SIGMOD 2024) · answerai-colbert-small: train your own late-interaction model by distillation (2024/25) · LitSearch: a literature-search benchmark (EMNLP 2024) · OpenScholar: RAG over 45M papers (Nature 2026) · NV-Retriever: what is a good hard negative? (2024) · Embedding compression improves domain adaptation (2026, laptop) · Search-o1 / BrowseComp-Plus / DCI-Agent (grep-based retrieval for agents, 2026) · HippoRAG 2 (ICML 2025) · RAG vs long context and Self-Route (EMNLP 2024) · Vec2Text: embeddings reveal the text (EMNLP 2023) · Fairness of exposure in rankings (KDD 2018) · Indirect prompt injection (Greshake et al., 2023) · TempRetriever: time-aware dense retrieval (WSDM 2026) · HistWords: diachronic word embeddings (ACL 2016) · OCR Hinders RAG (ICCV 2025) · CoIR: code retrieval benchmark (2024/25) · TAS-B: distil a cross-encoder into a bi-encoder with Margin-MSE (SIGIR 2021) and Beyond Hard Negatives (SIGIR 2026) · Unbiased LTR meets reality: the Baidu click dataset (SIGIR 2024) · Generative retrieval as multi-vector dense retrieval (SIGIR 2024) · TIGER: semantic IDs for generative recommendation (NeurIPS 2023) · LongEmbed: extending embedding models to long context (Zhu et al., EMNLP 2024, https://arxiv.org/abs/2404.12096) · SEAL: substrings as document identifiers (Bevilacqua et al., NeurIPS 2022, https://arxiv.org/abs/2204.10628) · Found in the Middle: permutation self-consistency against position bias in LLM rankers (Tang et al., NAACL 2024, https://arxiv.org/abs/2310.07712).

From the instructor's own group, ask before choosing: Citation-Driven Multi-View Training for Patent Embeddings: QaECTER and Sophia-Bench (Djemmal, Zuo, Gerdes & Guiller, FUSION 2026, https://arxiv.org/abs/2604.22897) and Sparse Coverage: Semantic Center Representations for Patent Prior-Art Retrieval (Zuo, Gerdes et al., CORIA-TALN 2026, https://arxiv.org/abs/2608.16918). Presenting them to their author is allowed; expect a well-informed discussant.