We investigate Dynamic Embedding Injection (DEI), a method for injecting retrieved document knowledge into language model intermediate layers as dense embeddings rather than context tokens. Across three QA datasets (SQuAD v2, NQ-open, TriviaQA) and two model architectures (Qwen3-1.7B Transformer, Qwen3.5-9B Gated DeltaNet hybrid), DEI reduces cross-entropy loss by 14.9–62.9% over no-retrieval baselines while using ~88% fewer context tokens than token-level RAG. A persistent ~65% gap with token-level RAG remains, consistent with an information-capacity bottleneck in residual-stream injection that lightweight LoRA adaptation did not close within our training budget. Code and experiment logs: https://github.com/2264K/dei
Kim (Sun,) studied this question.