hakeutumisilmiö

hakeutumisilmiö is the Finnish term for quantum entanglement, a nonclassical correlation between physical systems that arises when the quantum state of each system cannot be described independently of the state of the other(s). The phenomenon is characterised by the fact that measurements on one part of an entangled state instantaneously affect the outcome probabilities of measurements on the remaining parts, regardless of the spatial separation between them.

The concept was first formalised by Erwin Schrödinger in 1935 as a response to the Einstein–Podolsky–Rosen paradox, which highlighted apparent incompleteness of quantum mechanics. In practice, entanglement is produced by processes such as parametric down-conversion in nonlinear crystals, spontaneous emission of photon pairs, or spin exchange in atomic ensembles.

Applications of hakeutumisilmiö are central to quantum information science, enabling protocols like quantum teleportation, superdense coding, and quantum key distribution. Entanglement also underpins emerging technologies such as quantum computing, where it allows qubits to represent and process information in ways that surpass classical bits.

Experimental tests of the phenomenon, notably Bell‑inequality violations, have confirmed the nonlocal correlations predicted by quantum theory. The field continues to explore decoherence mechanisms, entanglement quantification, and the integration of entangled states into practical communication and computation systems.