Part VI — Quantum Circuits
With the mental model (Part II), the mathematics (Part III), the physics (Part IV), and multi-qubit states (Part V) in place, we can finally speak the working language of the field: the quantum circuit. Circuits are to quantum computing what assembly is to classical machines — low-level, universal, and the lingua franca of every paper, SDK, and hardware manual. This part has three movements: the notation itself (Ch. 15), the practice of programming with it in Qiskit (Ch. 16), and the rite of passage every serious quantum engineer should complete — building a state-vector simulator from scratch (Ch. 17). Everything in Parts VII–XIII assumes fluency here.