Vortex-enabled Andreev processes in quantum Hall-superconductor hybrids

Quantum Hall-superconductor heterostructures provide possible platforms for both Majorana zero modes and parafermionic generalizations.  Motivated by several recent experiments that successfully integrated these phases, we investigate transport through a proximitized integer quantum Hall edge---paying particular attention to the impact of vortices in the superconductor.  By examining the downstream conductance, we identify regimes in which sub-gap vortex levels mediate Andreev processes that would otherwise be frozen out in a vortex-free setup.  Moreover, we show that at finite temperature, and in the limit of a large number of vortices, the downstream conductance averages to zero, indicating that the superconductor effectively behaves like a normal contact.  We discuss these results in the context of existing transport measurements on quantum Hall-superconductor hybrids.