Gapless Symmetry-Protected Topological Order

Citation data:

Physical Review X, ISSN: 2160-3308, Vol: 7, Issue: 4

Publication Year:
Usage 31
Downloads 27
Abstract Views 4
Captures 28
Readers 28
Social Media 5
Tweets 5
Citations 4
Citation Indexes 4
Repository URL:
Scaffidi, Thomas; Parker, Daniel E.; Vasseur, Romain
American Physical Society (APS)
Physics and Astronomy; condensed matter physics; magnetism; topological insulators; Condensed Matter Physics; Physics
Most Recent Tweet View All Tweets
article description
We introduce exactly solvable gapless quantum systems in d dimensions that support symmetry-protected topological (SPT) edge modes. Our construction leads to long-range entangled, critical points or phases that can be interpreted as critical condensates of domain walls "decorated" with dimension (d - 1) SPT systems. Using a combination of field theory and exact lattice results, we argue that such gapless SPT systems have symmetry-protected topological edge modes that can be either gapless or symmetry broken, leading to unusual surface critical properties. Despite the absence of a bulk gap, these edge modes are robust against arbitrary symmetry-preserving local perturbations near the edges. In two dimensions, we construct wave functions that can also be interpreted as unusual quantum critical points with diffusive scaling in the bulk but ballistic edge dynamics.