Cluster State Quantum Computation
A computing model performing logic via measurements on a pre-entangled grid of qubits.
Cluster State Quantum Computation (CSQC) is a model for performing quantum computations based on a highly entangled multi-qubit state known as a cluster state. Unlike the circuit model, where quantum gates are applied sequentially to qubits, CSQC operates through a series of single-qubit measurements performed on this pre-prepared cluster state. The computation proceeds by choosing the order and bases of these measurements. The cluster state itself is typically generated through a process of entangling gates applied to an initial state of qubits, followed by measurements that effectively 'erase' the qubits from the computation while propagating the quantum information. This measurement-based approach offers potential advantages in terms of fault tolerance, as it can be more robust to certain types of errors. However, it also presents challenges in terms of state preparation and the complexity of designing measurement sequences for arbitrary algorithms. The universality of CSQC has been demonstrated, meaning any quantum computation can, in principle, be performed using this model.
graph LR
Center["Cluster State Quantum Computation"]:::main
Pre_quantum_entanglement["quantum-entanglement"]:::pre --> Center
click Pre_quantum_entanglement "/terms/quantum-entanglement"
Pre_qubit["qubit"]:::pre --> Center
click Pre_qubit "/terms/qubit"
Rel_linear_optical_quantum_computer["linear-optical-quantum-computer"]:::related -.-> Center
click Rel_linear_optical_quantum_computer "/terms/linear-optical-quantum-computer"
Rel_quantum_teleportation["quantum-teleportation"]:::related -.-> Center
click Rel_quantum_teleportation "/terms/quantum-teleportation"
Rel_topological_quantum_computation["topological-quantum-computation"]:::related -.-> Center
click Rel_topological_quantum_computation "/terms/topological-quantum-computation"
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🧠 Knowledge Check
🧒 Explain Like I'm 5
Imagine a big, tangled ball of [yarn](/en/terms/yarn) where each knot is a tiny quantum [bit](/en/terms/bit). Instead of pulling strings in a specific order like in a recipe, you poke and prod different parts of the yarn ball, and the way you poke tells the yarn ball what to do.
🤓 Expert Deep Dive
CSQC is a universal model of quantum computation, equivalent in power to the quantum circuit model. Its foundation lies in the properties of graph states, specifically cluster states, which are highly entangled states characterized by a specific stabilizer graph. Computation proceeds via adaptive single-qubit measurements. The choice of measurement basis for each qubit determines the subsequent evolution of the remaining qubits. This process can be viewed as a form of 'teleportation' of quantum information through the entangled resource. Key advantages include inherent robustness against certain types of decoherence and errors due to the measurement-based nature, potentially simplifying error correction schemes. However, the generation of large, high-fidelity cluster states is a significant experimental challenge. The universality is proven by showing that any quantum circuit can be translated into a sequence of measurements on a universal cluster state, often requiring a 'universal' initial state and a specific set of measurement bases.