Special Condensed Matter Theory Seminar: Zhen Bi, Penn State University, “Interaction enabled higher-order topological phases with subsystem symmetry”

Event time: 
Friday, May 13, 2022 - 10:30am to 11:30am
Sloane Physics Laboratory (SPL), Room 51 See map
217 Prospect Street
New Haven, CT 06511
Event description: 

Recently, the notion of topological states of matter has been extended to include their higher-order cousins. They refer to systems that host robust gapless hinge or corner modes albeit gapped surfaces. So far the exploration of higher-order topological phases is mostly focusing on free fermion systems with point group symmetry. In this work, we present a collection of three-dimensional higher-order symmetry-protected topological phases (HOSPTs) with gapless hinge modes that exist only in strongly interacting systems subject to subsystem symmetry constraints. We use a coupled wire construction to generate three families of microscopic lattice models: insulators with helical hinge modes, superconductors with chiral Majorana hinge modes, and fractionalized insulators with helical hinge modes that carry fractional charges. In particular, these HOSPTs do not require spatial symmetry protection but are instead protected by subsystem symmetries, and support “fractonic” quasiparticle excitations that move within only a low-dimensional sub-manifold of the system.
Host: Meng Cheng (m.cheng@yale.edu)