In quantum entanglement, when two particles are entangled, their quantum states become correlated in such a way that the measurement of one particle instantaneously affects the state of the other particle, regardless of the spatial separation between them. This phenomenon is known as "spooky action at a distance," as described by Albert Einstein, Boris Podolsky, and Nathan Rosen in the EPR paradox.
However, it is important to note that this instantaneous correlation between entangled particles does not allow for the transmission of classical information faster than the speed of light. This is because the measurement outcomes on either side appear random and are probabilistic in nature. Even though a change in one particle's state seems to instantaneously affect the other, this change does not convey any meaningful information until the results of repeated measurements are compared statistically.
The apparent contradiction with special relativity arises from the fact that the measurement outcomes cannot be predetermined or controlled in a way that would allow for faster-than-light communication. The observed correlations in entanglement are based on statistical patterns and cannot be exploited to transmit information instantaneously.
Quantum entanglement and its implications do challenge our intuitive understanding of cause and effect and the concept of locality, but they are consistent with the framework of quantum mechanics. The predictions and observations related to entanglement have been extensively tested and have consistently agreed with quantum theory.
Therefore, while the entangled particles may exhibit instantaneous correlations, the limitations on extracting meaningful information prevent the violation of Einstein's principle of causality or the transmission of information faster than the speed of light.