Spooky Action at a Distance: Quantum Entanglement Explained
NIST Discovers “Spooky Action,” Unlocking True Randomness for Quantum Leap Trust.
NIST researchers discovered “spooky action at a distance,” which concerned Albert Einstein. This finding solved a long-standing quantum physics problem and created CURBy, the Colorado University Randomness Beacon, a pioneering service that provides publicly available, verifiable, and actually unexpected random numbers.
Spooky distant action
Quantum entanglement was called “spooky action at a distance” by Einstein. Entanglement is the bizarre idea that two physically independent particles may have inherently connected properties before being measured. Einstein questioned this theory, and scientists hadn't been able to prove it almost completely until lately.
The NIST team performed rigorous Bell tests, named for Irish physicist John Bell. Bell’s 1964 hypothesis states that “local, pre-existing (i.e., realistic) conditions” can only explain a portion of measurement correlations. Any correlations beyond these limits would require quantum entanglement or faster-than-light transmission, which experts believe is impossible.
NIST scientist Krister Shalm stressed the significance of their findings: “The experiment is incompatible with local reality, or hidden local action, but you can’t establish quantum mechanics. The results match quantum theory' predictions of entangled particles' strange behaviour. He added, “If God does play dice with the universe, then you can turn that into the best random number generator that the universe allows”.
Two detectors in separate rooms of a huge Boulder laboratory building received identical pairs of photons from the NIST team. The detectors were 184m apart. Produce entangled photon pairs with highly coupled polarisations and prescribed orientations. As photons travelled through each analyser at the detectors, a random number generator chose one of two polarisation settings. Photons that matched the analyser setting were detected over 90% of the time.
The findings were conclusive. Both detectors found 6,378 photons in 30 minutes. The researchers projected 0.0000000059, or 1 in 170 million, local realism would induce such effects. This result exceeded the particle physics community's “5 sigma” discovery threshold, demonstrating quantum entanglement and ruling out local realistic models.
A NIST experiment
A major achievement of the NIST experiment was closing the three key “loopholes” that had compromised Bell tests:
Because NIST's ultrafast single-photon detectors are made of superconducting nanowires and operate at 90% efficiency (approximately 75% system efficiency), the detected photons and measurement results were properly indicative of the total.
No faster-than-light communication: The detectors measured photons from the same pair within a few hundred nanoseconds of each other, excluding the possibility of light-speed communication. Freedom to choose: To ensure detector settings were unmanipulated, random number generators outside the photon source's “light cone” were utilised to choose them. More runs incorporated randomisation from famous films, TV shows, and Pi numbers to eliminate hidden variables like power grid oscillations without modifying the results.
This 2015 Physical Review Letters study showed quantum physics' underlying unpredictability. Using this actual randomness and this deep understanding, NIST and the University of Colorado Boulder created CURBy, the Colorado University Randomness Beacon.
The Need for True Randomness
Unpredictability From fair games and public lotteries to strong cybersecurity and cryptography, randomisation is vital. Traditional “random” numbers generated by computer algorithms are frequently “pseudo-random” and seem unpredictable. If given enough information, a skilled hacker or attentive observer could spot trends and compromise security. “True randomness is something that nothing in the universe can predict in advance,” Krister Shalm reiterated.
How CURBy Works and Builds Trust
The first random number generator service, Trust CURBy, comes from quantum nonlocality's “spooky action”. NIST constantly runs a Bell test to produce unprocessed, random data. Created entangled photon pairs are sent to separate labs for polarisation measurements. Researchers can verify photon readings' unpredictability by examining pair properties. The 250,000-times-per-second method refines millions of “quantum coin flips” into 512 random bits of binary code.
NIST and its collaborators created the Twine protocol, which uses blockchain technology compatible with quantum computing to establish tamper-proof trust. This method assigns a “hash” or digital fingerprint to each batch of data to trace and confirm each randomness generating phase. “The Twine protocol lets us weave together all these other beacons into a tapestry of trust,” said project research assistant Jasper Palfree. This prevents data manipulation and allows a multi-entity randomisation network.
The entire CURBy system is open source, so anyone can test and contribute. Transparency is needed for the public to trust jury selection, audits, and public lotteries.
NIST's Boulder and Gaithersburg campuses, the Jet Propulsion Laboratory, the University of Illinois, Waterloo, Moncton, and Barcelona Institute of Science and Technology collaborated to develop. NIST got DARPA funds for its work.