Overview
Direct Answer
Quantum entanglement is a quantum mechanical phenomenon in which two or more qubits become correlated such that measuring the state of one instantaneously determines the state of the other, regardless of spatial separation. This correlation persists without any classical signal travelling between the particles.
How It Works
Entanglement occurs when qubits are prepared in a joint quantum state where their properties remain undefined until measurement. When one qubit is measured and its state collapses, the correlated qubit's state immediately becomes determined. This interdependence arises from shared quantum information encoded in the combined wavefunction, not from prior agreement or hidden variables.
Why It Matters
Entanglement enables quantum computers to perform parallel computations exponentially faster than classical systems for specific problems. It is essential for quantum algorithms such as Shor's factorisation and Grover's search, making it critical for cryptography, optimisation, and drug discovery applications where computational speed directly impacts time-to-market and competitive advantage.
Common Applications
Entanglement underpins quantum key distribution protocols used in secure communications, quantum teleportation experiments, and distributed quantum computing architectures. It is leveraged in quantum simulation for modelling molecular behaviour and in quantum sensing for enhanced measurement precision.
Key Considerations
Entanglement is fragile; environmental interference causes decoherence, degrading quantum states within microseconds. Scaling entanglement across large numbers of qubits whilst maintaining coherence remains a fundamental engineering challenge limiting current quantum processor capabilities.
More in Quantum Computing
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Quantum Volume
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Quantum Chemistry
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Trapped Ion Qubit
Hardware & ImplementationA qubit implementation using individual ions confined by electromagnetic fields and manipulated by laser beams.