A recent paper by Xie Chen Symmetry Fractionalization in Two Dimensional Topological Phases is available in Review in Physics. Symmetry fractionalization describes the fascinating phenomena that excitations in a 2D topological system can transform under symmetry in a fractional way. For example in fractional quantum Hall systems, excitations can carry fractional charges while the electrons making up the system have charge one. An important question is to understand what symmetry fractionalization (SF) patterns are possible given different types of topological order and different global symmetries. The paper goes on to review examples where the bulk states are topological insulators, topological superconductors, or have other symmetry protected topological orders.
The paper is also featured in an editorial review by Nai-Chang Yeh “the article by Chen provides an interesting perspective of recent theoretical developments in the research of interacting two-dimensional topological phases. Given the relevance of fractionalized topological excitations to topological quantum science and strongly interacting topological systems, eventual experimental detections of SF beyond the FQHE are of paramount importance to the advances of the field.” Read the full review article, Fractionalized quantum excitations in correlated two-dimensional topological phases