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Physicists shed light on relation between entanglement and nonlocality

01.01.70

New research from the University of Bristol may disprove a long-standing conjecture made by one of the founders of quantum information science: That quantum states featuring 'positive partial transpose,' a particular symmetry under time-reversal, can never lead to nonlocality.

When it comes to space and time, modern physics defies our intuition in the most dramatic way. Einstein's relativity theory tells us that time and space are intimately related and that absolute time is an illusion. Quantum mechanics, however, is at rest, and its predictions are perhaps even more astonishing than those of relativity.

In a nutshell, quantum theory tells us that two entangled particles behave as a single physical object, no matter how far apart they are. If a measurement is performed on one of these particles, the state of its distant twin is instantaneously modified.

This effect leads to quantum nonlocality, the fact that the correlation between results of local measurements performed on these particles are so strong, that they could not have been obtained from any pair of classical systems, such as two computers. To cut a long story short, it is as if quantum particles live outside space-time—and experiments confirm this.

Source: R & D Magazine