Condensed Matter Physics Seminar

One way to understand 3D topological (band) insulators is that they must be distinct phases of matter since they have surface states that cannot exist (with the same symmetry) in purely 2 dimensional systems. This criterion can also be applied to interacting systems, and has led to a rapidly growing understanding of symmetry protected phases of matter in bosonic systems (where it exists only in the presence of strong interactions). I will present a model that realizes one such bosonic symmetry-protected phases: the model is fully time-reversal invariant in 3D, but realizes a surface state that cannot preserve time-reversal in 2D.