ior ▁Dan cing ▁ ▁Television ▁and ▁variety ▁No che ▁de ▁est rell as , ▁a ▁Latin ▁American ▁musical ▁variety ▁television ▁show ▁series ▁No che ▁de ▁est rell as ▁de ▁F idel ity , ▁a ▁famous ▁series ▁of ▁musical ▁events ▁by ▁W F ID , ▁Radio ▁F idel ity <0x0A> </s> ▁Mag net ic ▁topological ▁ins ul ators ▁are ▁three ▁dimensional ▁magnetic ▁materials ▁with ▁a ▁non - t rivial ▁topological ▁index ▁protected ▁by ▁a ▁symmetry ▁other ▁than ▁time - re vers al . ▁In ▁contrast ▁with ▁a ▁non - mag net ic ▁topological ▁ins ulator , ▁a ▁magnetic ▁topological ▁ins ulator ▁can ▁have ▁naturally ▁g apped ▁surface ▁states ▁as ▁long ▁as ▁the ▁quant izing ▁symmetry ▁is ▁broken ▁at ▁the ▁surface . ▁These ▁g apped ▁surfaces ▁exhib it ▁a ▁top olog ically ▁protected ▁half - quant ized ▁surface ▁anom alous ▁Hall ▁conduct ivity ▁() ▁per pend icular ▁to ▁the ▁surface . ▁The ▁sign ▁of ▁the ▁half - quant ized ▁surface ▁anom alous ▁Hall ▁conduct ivity ▁depends ▁on ▁the ▁specific ▁surface ▁term ination . ▁ ▁Theory ▁ ▁Ax ion ▁coupling ▁ ▁The ▁ ▁classification ▁of ▁a ▁ 3 D ▁cry st all ine ▁topological ▁ins ulator ▁can ▁be ▁understood ▁in ▁terms ▁of ▁the ▁ax ion ▁coupling ▁. ▁A ▁scalar ▁quantity ▁that ▁is ▁determined ▁from ▁the ▁ground ▁state ▁wave function ▁▁▁ ▁. ▁ ▁where ▁▁ ▁is ▁a ▁sh orth and ▁notation ▁for ▁the ▁Ber ry ▁connection ▁matrix ▁, ▁ ▁where ▁ ▁is ▁the ▁cell - period ic ▁part ▁of ▁the ▁ground ▁state ▁Blo ch ▁wave function .