Hyunwoong Bae
Author directory2026
Axis-LoRA: Probing and Adapting Embedding Models for Personal-Memory Retrieval
Dohoon Kim | Junho Park | Hyunwoong Bae | Seyoon Kim | Taesup Moon
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Dohoon Kim | Junho Park | Hyunwoong Bae | Seyoon Kim | Taesup Moon
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
As LLMs are increasingly asked questions about a user’s personal experiences, retrieval must distinguish memories by time, place, person, and event. Current personal-memory pipelines rely on frozen dense embedding models to embed memories for retrieval, but we find that these models do not capture the four axes well. Swapping a memory’s date or place barely shifts its embedding, and a trained projection on top of the frozen embedding does not recover the missing signal. The problem lives inside the model, where each axis is encoded by a distinct attention-head pattern. Guided by these findings, we propose Axis-LoRA, a per-axis adapter that places four LoRA branches inside the embedding model and combines them via a per-query gate. Across three standard embedding models evaluated on LongMemEval, ATM-Bench, and LoCoMo, Axis-LoRA improves 4-benchmark mean R@10 by +1.38 to +1.59 pp while training only a small fraction of the base parameters on a small axis-counterfactual training set.