Extended Data Fig. 5: Triply-degenerate points at K and M, and their frame charges.
From: Experimental observation of non-Abelian topological acoustic semimetals and their phase transitions
Band structure in the vicinity of the triply-degenerate points K (a) and M (b), with the encircling base loops lK and lM. c The accumulated geometric frame angle computed over the base loops lK (full line) and lM (dashed line). The triply-degenerate point at K exhibits a total frame angle of π indicating the non-Abelian frame charge k, while the triply-degenerate point at M exhibits a total frame angle of 2π indicating the non-Abelian frame charge of −1.
