Enhancing Quantum Optimization with Parity Network Synthesis

This paper examines QAOA in the context of parity network synthesis. We propose a pair of algorithms for parity network synthesis and linear circuit inversion. Together, these algorithms can build the diagonal component of the QAOA circuit, generally the most expensive in terms of two qubit gates. We compare the CNOT count of our strategy to off-the-shelf compiler tools for random, full, and graph-based optimization problems and find that ours outperforms the alternatives.