The experiment setup used by Prof. Yin's group to measure the speed of entanglement
Space-time diagram of Prof. Yin's experiment. The entangled photons were generated at E, but the decisions about which measurements to make are not located within E's future light cone, meaning that those decisions cannot be affected by the generation process
Niels Bohr and Albert Einstein debating quantum theory in the mid 1920s
The speed of entanglement dynamics is at least 10,000 times faster than light according to Prof. Juan Yin and colleagues ( Photo: Shutterstock)
Quantum entanglement, one of the odder aspects of quantum theory, links the properties of particles even when they are separated by large distances. When a property of one of a pair of entangled particles is measured, the other "immediately" settles down into a state compatible with that measurement. So how fast is "immediately"? According to research by Prof. Juan Yin and colleagues at the University of Science and Technology of China in Shanghai, the lower limit to the speed associated with entanglement dynamics – or "spooky action at a distance" – is at least 10,000 times faster than light.
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