Corner Modes and Ground-State Degeneracy in Models with Gauge-Like Subsystem Symmetries

Understand

Subsystem symmetries are intermediate between global and gauge symmetries.

• One can treat these symmetries either like global symmetries that act on subregions of a system, or gauge symmetries that act on the regions transverse to the regions acted upon by the symmetry.
• We show that this latter interpretation can lead to an understanding of global, topology-dependent features in systems with subsystem symmetries.
• We demonstrate this with an exactly-solvable lattice model constructed from a 2D system of bosons coupled to a vector field with a 1D subsystem symmetry.