This skill extends quantum computation to systems composed of multiple qubits. Learners examine how multi-qubit states are represented, how quantum operations scale beyond single-qubit systems, and how entanglement enables computational behaviours that have no classical analogue. The gate model of quantum computation is introduced as a framework for describing quantum algorithms.

• QC1.1 Foundations of Quantum Computing and Qubits
• QC1.2 Single-Qubit Systems

• Explain how multi-qubit quantum states are represented using tensor products.
• Differentiate between sequential and parallel applications of single-qubit gates in multi-qubit systems.
• Describe the function of common multi-qubit gates, including controlled-NOT (CNOT) gates and SWAP gates, which exchange the states of two qubits.
• Explain the concept of entanglement and describe Bell states as canonical examples.
• Summarise the impact of entanglement on the classical simulability of quantum systems.
• Describe how measurement operates in multi-qubit systems.
• Explain the gate model of quantum computation and the notion of universal gate sets.