Entanglement is one of the properties specific to quantum particles. When two photons become entangled, for instance, the quantum state of the first will correlate perfectly with the quantum state of the second, even if they are at a distance from one another. But what happens when three pairs of entangled photons are placed in a network? Researchers at the University of Geneva (UNIGE), Switzerland, working in partnership with Tehran's Institute for Research in Fundamental Sciences (IPM), have proved that this arrangement allows for a new form of quantum correlation in theory. When the scientists forced two photons from separate pairs to become entangled, the connection was also made with their twin photon present elsewhere in the network, forming a highly correlated triangle. These results, published in the journal Physical Review Letters, create the potential for new applications in cryptography.
“Entanglement involves two quantum particles—photons, for example—forming a single physical system in spite of the distance between them. Every action performed on one of the two photons has an impact on its "twin" photon. This principle of entanglement leads to quantum non-locality: … “
