Agentic Quantum Architecture (AQA): A Formal Hybrid Architecture for Agentic Quantum–Classical Computation

Agentic Quantum Architecture (AQA) is a layered, formally specified architecture in which an autonomous agent decides, per operation and under explicit uncertainty, whether a computation should run on classical hardware, on a classical simulation of a quantum circuit, or on a physical quantum processor, and accepts no result that has not passed an independent check. AQA treats the quantum processor as a scarce, noisy, probabilistic co-processor reached through compilation, queueing, and sampling, not as a substrate for agent reasoning. The architecture comprises eight layers across four planes: agentic intelligence, planning and decision, classical computation, quantum computation, quantum-classical coordination, memory and state, verification and reliability, and security and governance. We formalize a unified agent state, a belief-space action-selection rule grounded in rational metareasoning, a 10-field typed Quantum Workload Specification (QWS), an end-to-end cost and latency model for routing, a statistical measurement-to-evidence pipeline, and formal acceptance conditions for computational results. The core mechanism is a conservative lower-confidence-bound (LCB) routing rule: an operation is delegated to quantum hardware only when a lower confidence bound on its net utility advantage—accounting for encoding, compilation, queueing, shot overhead, error mitigation, post-processing, verification, and expected failure—is strictly positive. Under present NISQ constraints, classical execution will prevail for most workloads, which the architecture treats as sound decision-making rather than a defect. A five-phase implementation roadmap and ten falsifiable research questions are provided.