A new experiment provides the best evidence yet that the common-sense concept of locality — that an event on Earth can’t immediately influence what happens on Mars, for instance — doesn’t apply in the quantum realm.
Researchers have long thought that quantum theory is nonlocal. But airtight experimental confirmation has been difficult to achieve. Now a new paper, posted online August 26 at arXiv.org, closes two loopholes that had cast a smidgen of doubt on previous results from a crucial test.
“Nonlocality is so fundamental and so important for our worldview of quantum mechanics that it’s important to achieve such a result,” says Nicolas Gisin, a quantum physicist at the University of Geneva. An apparatus similar to the one used in the new experiment could be used to build extremely secure communication networks.