Published: April 15, 2025 | Author: Prof. Richard Feynman

The Quantum Connection

When two particles become entangled, they form a single quantum system regardless of the distance separating them. The quantum state of each particle cannot be described independently of the other – they are fundamentally connected in ways that defy classical physics.

Einstein's "Spooky Action at a Distance"

Albert Einstein famously referred to quantum entanglement as "spooky action at a distance." He was troubled by the implication that measuring one particle could instantaneously affect another particle, even if separated by vast distances, seemingly violating the speed of light limit for information transfer.

Measurement and Collapse

When a measurement is performed on one entangled particle, it instantaneously determines the corresponding property of its partner. Before measurement, the particles exist in a superposition of states; after measurement, both particles "collapse" into definite, correlated states.

Bell's Inequality

In 1964, physicist John Bell developed a theorem that allowed scientists to experimentally test whether quantum entanglement could be explained by classical "hidden variables." Subsequent experiments confirmed quantum mechanics' predictions, demonstrating that entanglement is a genuine quantum phenomenon that cannot be explained classically.

Applications of Entanglement

Quantum entanglement is not merely a theoretical curiosity but forms the foundation for revolutionary technologies. Quantum computing leverages entanglement to perform calculations impossible for classical computers. Quantum cryptography uses entangled particles to create theoretically unhackable communication channels. Quantum teleportation protocols utilize entanglement to transfer quantum states between distant locations.