Scaling LLMs horizontally: hidden-state coupling without weight modification [R]

In three linesResidual Coupling (RC) connects frozen language models in parallel via lightweight learned linear projections, without weight modification. Linear bridges read hidden states from one model and inject additive updates into another's residual stream. On medical data, RC reduces perplexity to 11.02 vs 56.80 for MoE (+80.7%), and improves TruthfulQA by 9.1 percentage points.

Summary generated by Claude — human-verified