Relation Between Scattering Matrix Topological Invariants and Conductance in Floquet Majorana Systems

We analyze the conductance of a one-dimensional topological superconductor periodically driven to host Floquet Majorana zero modes for different configurations of coupling to external leads. We compare the conductance of constantly coupled leads, as in standard transport experiments, with the stroboscopic conductance of pulsed coupling to leads used to identify a scattering matrix topological index for periodically driven systems. We find that the sum of the DC conductance at voltages corresponding to integer multiples of the driving frequency is quantitatively close to the stroboscopic conductance at all voltage biases. This is consistent with previous work which indicated that the summed conductance at resonances is quantized. We quantify the difference between the two in terms of the widths of their respective resonances and analyze that difference for two different stroboscopic driving protocols of the Kitaev chain. While the quantitative differences are protocol dependent, we find that generically the discrepancy is larger when the zero-mode weight at the end of the chain depends strongly on the offset time between the driving cycle and the pulsed coupling period.