đ€ AI Summary
To address the low efficiency, excessive resource consumption, and difficulty in simultaneously ensuring robustness and diversity in manual quantum circuit design for the NISQ era, this work introduces Generative Flow Networks (GFlowNets) to quantum circuit synthesis for the first time, proposing an end-to-end trainable generative framework. It models circuit construction as a flow propagation process over a directed acyclic graph (DAG), guided by a user-defined multi-objective reward function to enable sequential sampling of diverse, high-quality circuitsâdeparting from conventional single-point optimization paradigms. Experiments on molecular ground-state estimation, Max-Cut, and quantum image classification demonstrate that the synthesized circuits achieve 10â30Ă compression over state-of-the-art methods in parameter count, gate count, and circuit depth, without sacrificing accuracy, while maintaining robustness under realistic quantum hardware noise.
đ Abstract
Designing efficient quantum circuits is a central bottleneck to exploring the potential of quantum computing, particularly for noisy intermediate-scale quantum (NISQ) devices, where circuit efficiency and resilience to errors are paramount. The search space of gate sequences grows combinatorially, and handcrafted templates often waste scarce qubit and depth budgets. We introduce extsc{FlowQ-Net} (Flow-based Quantum design Network), a generative framework for automated quantum circuit synthesis based on Generative Flow Networks (GFlowNets). This framework learns a stochastic policy to construct circuits sequentially, sampling them in proportion to a flexible, user-defined reward function that can encode multiple design objectives such as performance, depth, and gate count. This approach uniquely enables the generation of a diverse ensemble of high-quality circuits, moving beyond single-solution optimization. We demonstrate the efficacy of extsc{FlowQ-Net} through an extensive set of simulations. We apply our method to Variational Quantum Algorithm (VQA) ansatz design for molecular ground state estimation, Max-Cut, and image classification, key challenges in near-term quantum computing. Circuits designed by extsc{FlowQ-Net} achieve significant improvements, yielding circuits that are 10$ imes$-30$ imes$ more compact in terms of parameters, gates, and depth compared to commonly used unitary baselines, without compromising accuracy. This trend holds even when subjected to error profiles from real-world quantum devices. Our results underline the potential of generative models as a general-purpose methodology for automated quantum circuit design, offering a promising path towards more efficient quantum algorithms and accelerating scientific discovery in the quantum domain.