Rotary Position Embedding Converts Absolute Indices into Relative Attention Phases
Self-attention can compare token content without assigning an order to token positions. Rotary Position Embedding (RoPE) inserts position into that comparison by rotating paired coordinates of queries and keys. Each token receives an absolute rotation angle, yet the query-key inner product reduces those two absolute angles to their difference. That algebraic cancellation is the central mechanism. RoPE does not add a position vector to the hidden state. It changes the orientation of query and key components before their dot product is evaluated.