Experimental evidence of non-Abelian conservation rule for multiple interacting exceptional points
Qicheng Zhang, Yufei Leng, Cui-Xian Guo, Liangjun Qi, Shuaishuai Tong, Haiping Hu, and Chunyin Qiu
Phys. Rev. B 112, L020101 (2025) - Published 21 July, 2025
The authors experimentally uncover here a surprising twist in non-Hermitian physics: exceptional points—previously thought to annihilate in pairs—can instead coalesce into new, higher-order ones. Using sound waves in a specially designed resonator array, the authors track how multiple exceptional points split, interact and collide. The results validate a non-Abelian conservation rule that governs their collective behavior, including topological charge transmutations. This counterintuitive discovery challenges conventional wisdom and opens exciting new possibilities for controlling sound waves in engineered systems.

















