Pristine and pseudogapped boundaries of deconfined quantum critical points

Bulk topology and criticality can each give rise to nontrivial boundary phenomena. This work shows that their interplay, at unconventional quantum critical points between a quantum spin Hall insulator and a superconductor, produces an unexpectedly rich landscape of edge states. In addition to the usual quantum spin Hall edge modes, the authors identify novel ``pseudogapped'' chiral fermions, characterized by a strongly suppressed spectral function and super--power-law decay of the Green's function.