Hybrid retrieval-augmented generation for scientific question answering
A hybrid RAG pipeline over the SciFact corpus: BM25 first-stage retrieval, ColBERT-style late-interaction re-ranking, and citation-backed generation from a 4-bit quantised Qwen2.5-3B model. The ColBERT projection layer was fine-tuned with InfoNCE on BM25-mined hard negatives.
| nDCG@10 | AP@10 | RR@10 | Re-ranking latency |
|---|---|---|---|
| 0.6858 | 0.6479 | 0.6581 | 43.1 ms / query |