Quantum entanglement is a phenomenon in quantum mechanics where two or more particles become correlated in such a way that the state of one particle cannot be described independently of the others. This correlation persists even if the particles are physically separated by large distances.
When particles are entangled, their quantum states are described by a joint or composite state rather than individual states. The interesting aspect of entanglement is that the properties of each particle are not determined until they are measured, and the act of measuring one particle's state instantaneously affects the state of the other, regardless of the distance between them. This instantaneous correlation is often referred to as "spooky action at a distance," a term coined by Albert Einstein.
Quantum entanglement plays a crucial role in quantum computing. In quantum computing, quantum bits or qubits are used as the fundamental units of information. Qubits can be in a superposition of both 0 and 1 states simultaneously, thanks to the principles of quantum mechanics. However, by themselves, individual qubits are not sufficient to harness the full power of quantum computing.
Entanglement allows multiple qubits to be linked together in a highly correlated way. When qubits are entangled, their combined state becomes a superposition of all possible states of the system. This enables quantum computers to perform certain computations more efficiently than classical computers.
In quantum computing, entanglement is used to perform quantum operations, such as quantum gates, on multiple qubits simultaneously. By entangling qubits and applying quantum operations, quantum computers can perform parallel computations and process information in ways that are not possible with classical computers. Entanglement provides the computational advantage and enables quantum algorithms to solve certain problems more efficiently, such as factorizing large numbers or simulating quantum systems.
However, entanglement is also a delicate phenomenon that is easily disrupted by interactions with the surrounding environment, a process known as decoherence. Maintaining and manipulating entangled states is a major challenge in quantum computing, and researchers are actively exploring ways to overcome these challenges to build practical and scalable quantum computers.