C. Stein, S. Klikovits, M. Wimmer: Revisiting Crossover Effectiveness in Quantum Circuit Synthesis, the Genetic and Evolutionary Computation Conference (GECCO 2026@San José), San Antonio de Belén, Alajuela, Costa Rica, July 13-17, 2026 acctepted for publication.
We investigate the role of crossover in Quantum Circuit Synthesis (QCS) with Genetic Algorithms (GAs) using the commonly used list encoding. We start with a preliminary investigation into the level and development of epistasis in QCS. Then, we perform three experiments comparing the performance of a GA with one-point crossover against a search strategy that only uses mutation. For the gate and qubit counts we tested, the GA with crossover performed on par with the mutation-only variant on one of the tested syntheses targets and underperformed on the remaining two. This motivates further research on the suitability of standard crossover Operators for QCS and prompts the need to develop more efficient, problemspecific encodings and operators.