I wonder how this different from HyDE. https://docs.haystack.deepset.ai/docs/hypothetical-document-...
It would be interesting to see a performance comparison, it certainly seems the most relevant one (that or an ablation of their "memory model" with the LLMs upon which they are based).
Section 2.2 of the paper[1] goes into this in more detail. They pretrain the draft model using the redpajama dataset, followed by a supervised fine-tuning step. The training objective "aims to maximize the generation probability of the next token given the KV cache of the previous memory tokens".
This suggests that any model with long context and good retrieval performance could do the same job (and maybe better in the case of the SOTA frontier models).