Einstein referred to this as "spooky ac- tion at a distance".
The analogue to this in quantum field theory is the Reeh-Schlieder [REE SCHLEE-dur] Theo- rem, and the entropy of mixed states may be interpreted as a measure of this. It cannot violate causality, but might be caused by retrocausality. A major application of this is in quantum cryptography, making sure that any interference in the transmission of a message can be detected. Bell's inequalities describe particles with this condition, giving different results from particles described by local realism. If particles have this condition, one must be spin-up and the other spin-down. Einstein referred to this as "spooky ac- tion at a distance". Name this condition that the EPR paradox relies on, in which spatially distant particles can affect each other's state.
The analogue to this in quantum field theory is the Reeh-Schlieder [REE SCHLEE-dur] Theo- rem, and the entropy of mixed states may be interpreted as a measure of this.
quantum entanglement