Levin-Wen models are microscopic spin models for topological phases of matter in (2+ 1)-dimension. We introduce a generalization of such models to (3 + 1)-dimension based on unitary braided fusion categories, al...Levin-Wen models are microscopic spin models for topological phases of matter in (2+ 1)-dimension. We introduce a generalization of such models to (3 + 1)-dimension based on unitary braided fusion categories, also known as unitary premodular categories. We discuss the ground state degeneracy on 3-manifolds and statistics of excitations which include both points and defect loops. Potential con- nections with recently proposed fractional topological insulators and projective ribbon permutation statistics are described.展开更多
文摘Levin-Wen models are microscopic spin models for topological phases of matter in (2+ 1)-dimension. We introduce a generalization of such models to (3 + 1)-dimension based on unitary braided fusion categories, also known as unitary premodular categories. We discuss the ground state degeneracy on 3-manifolds and statistics of excitations which include both points and defect loops. Potential con- nections with recently proposed fractional topological insulators and projective ribbon permutation statistics are described.