  Routing plays an important role in programming noisy, intermediate-scale
quantum (NISQ) devices, where limited connectivity in the register is overcome
by swapping quantum information between locations. However, routing a quantum
state using noisy gates introduces non-trivial noise dynamics, and deciding on
an optimal route to minimize accumulated error requires estimates of the
expected state fidelity. Here we validate a model for state-dependent routing
dynamics in a NISQ processor based on correlated binary noise. We develop a
composable, state-dependent noise model for CNOT and SWAP operations that can
be characterized efficiently using pair-wise experimental measurements, and we
compare model predictions with tomographic state reconstructions recovered from
a quantum device. These results capture the state-dependent routing dynamics
that are needed to guide routing decisions for near-real time operation of NISQ
devices.
