We present a post-compilation quantum circuit optimization technique that
takes into account the variability in error rates that is inherent across
present day noisy quantum computing platforms. This method consists of
computing isomorphic subgraphs to input circuits and scoring each using
heuristic cost functions derived from system calibration data. Using standard
algorithmic test circuits we show that it is possible to recover on average
nearly 40% of missing fidelity using better qubit selection via efficient to
compute cost functions. We demonstrate additional performance gains by
considering qubit placement over multiple quantum processors. The overhead from
these tools is minimal with respect to other compilation steps such as qubit
routing as the number of qubits increases. As such, our method can be used to
find qubit mappings for problems at the scale of quantum advantage and beyond.Comment: 8 pages, 6 figure