Optimal Control of Unknown Collective Spin Systems via a Neural Network Surrogate

Quantum optimal control (QOC) relies on accurately modeling system dynamics and is often challenged by unknown or inaccessible interactions in real systems. Taking an unknown collective spin system as an example, this work introduces a machine-learning-based, data-driven scheme to overcome the confronted challenges, with a trained neural network (NN) assuming the role of a surrogate model that captures the system’s dynamics and subsequently enabling QOC to be performed on the NN instead of on the real system. The trained NN surrogate proves effective for practical QOC tasks, and is further demonstrated to be adaptable to different experimental conditions, remaining robust across varying system sizes and pulse durations.