The question revolves around a phenomenon called quantum entanglement, which predicts that changing one particle instantaneously changes the other—even if they are on opposite sides of the galaxy, 100,000 light-years apart.
Einstein called this idea “spooky action at a distance.” And he dismissed it, arguing that nothing could move faster than light, so entanglement couldn’t be real. Instead, he proposed that unknown “local factors” must determine the strange properties of these so-called entangled particles.
So how did Hanson prove him wrong? He conducted an experiment that builds on the work of a physicist named John Bell. In the 1960s, Bell argued that Einstein’s theory could be tested by separating a pair of entangled particles far enough so that local forces could not act on both of them at the same time and seeing how often their properties correlated. Physicists would also have to take enough measurements to prove their results were statistically valid.
Hanson is the first to conduct an experiment that does both. It is the strongest proof of quantum theory to date.
His conclusion raises all sorts of questions about the nature of the universe: What physical mechanism entangles particles? How do they communicate faster than light? If it works with an electron, why not a chair? What does this say about the structure of our universe?
Quantum entanglement also has a practical side. It could be used in communications, computing, and especially, cryptography. It might provide a physical basis for protecting privacy in ways that can never be broken.
The Kavli Foundation hosted a Google+ Hangout to learn more about our surprising quantum universe, and how we can turn theory into practical engineering.
About the Participants
RONALD HANSON – is the Antoni van Leeuwenhoek Professor at Delft University of Science and Technology and a member of the school’s Kavli Institute of Nanoscience. He has conducted the strongest test of quantum entanglement yet.
RENATO RENNER – heads the Swiss Federal Institute of Technology (ETH), Zurich’s Institute for Theoretical Physics and the Quantum Information Theory (QIT) Group. He is a leader in applying quantum physics to data security.
ALAN BROWN (moderator) – is a freelance journalist and writer who specializes in science, engineering, and technology. He has been covering nanoscience and nanotechnology for more than 25 years.