Higher-Dimensional Rotary Position Embedding

Yixing Li, Ruobing Xie, Yudong Zhang, Yushi Bai, Samm Sun, Yu Cheng


Abstract
Transformers rely on position embedding mechanisms in long context modeling in most cases. Rotary Position Embedding (RoPE) embeds positional information with independent 2D rotations, forming relative position terms in self-attention. However, its pairwise, block-based, and decoupled structure limits deep mixing and robustness across channels. We propose HD-RoPE, which extends RoPE from independent 2D rotations to higher-dimensional rotations and introduces a Paley-I orthogonal basis to obtain balanced, isotropic, and dense phase mixing within each rotation subspace. This significantly enhances channel coupling and rotational degrees of freedom while maintaining orthogonal stability and the relative position closure property. Furthermore, HD-RoPE is easily optimized for engineering efficiency without introducing additional trainable parameters. We have conducted extensive evaluation results demonstrating that HD-RoPE achieves significant performance improvements over standard RoPE across various popular benchmarks and in both long and short contexts.
Anthology ID:
2026.findings-emnlp.2406
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
51677–51692
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2406/
DOI:
Bibkey:
Cite (ACL):
Yixing Li, Ruobing Xie, Yudong Zhang, Yushi Bai, Samm Sun, and Yu Cheng. 2026. Higher-Dimensional Rotary Position Embedding. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 51677–51692, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Higher-Dimensional Rotary Position Embedding (Li et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2406.pdf