Distant stars as source of randomness constrains loophole in entanglement experiments
Digitized Sky Survey/STScI/NASA, CDS
The spookiness of quantum mechanics has gone cosmic.
Physicists have used starlight to perform a “Bell test” to verify the strange nature of quantum mechanics. For decades, such tests have repeatedly confirmed quantum physics’s quirks, but the tests contained loopholes. While the major loopholes have already been closed (SN: 12/26/15, p. 24), a lingering caveat remained, regarding whether the measurement equipment’s settings were chosen randomly. To tackle that loophole, scientists used the starlight as a source of randomness. Quantum mechanics emerged unscathed, physicists from the United States and Austria reported online November 22 at arXiv.org.