Higher-bracket structure of density operators in Weyl fermion systems and topological insulators
Higher-bracket structure of density operators in Weyl fermion systems and topological insulators
We study the algebraic structure of electron density operators in gapless Weyl fermion systems in $d=3,5,7,\ensuremath{\cdots}$ spatial dimensions and in topological insulators (without any protecting symmetry) in $d=4,6,8,\ensuremath{\cdots}$ spatial dimensions. These systems are closely related by the celebrated bulk-boundary correspondence. Specifically, we study the higher bracket---a generalization of commutator for …