We all knew that quantum physics was, well, strange, and now scientists have come one step closer to confirming its strangeness.
Quantum physics is the branch of physics that describes physical phenomena at the microscopic level. It does so remarkably well. It also lies at the foundation of modern technology, from MRI scanners to your iPod's hard drive. However, much of what occurs in quantum mechanics defies normal human intuition. A hallmark of this is the concept of entanglement, whereby two particles interact with each other even when separated by a great distance.
Einstein, who described the phenomenon as "spooky action at a distance," opposed quantum mechanics until the day he died, especially given its vast contradiction to his idea of how the universe operates on a large scale. "God doesn't play dice," he famously stated, referencing the randomness inherent in the subatomic theory.
"Quantum mechanics is a wonderful theory that scientists use very successfully," study co-author and physicist at the University of Vienna Marissa Giustina said. "But it makes some strange predictions."
But despite the accuracy of quantum mechanics, scientists have held on to the possibility that experimental results were caused by particles "exploiting" weaknesses in experimental setups. A team of scientists led by Austrian physicist Anton Zeilinger has now closed one such loophole, based on an experiment with photons.
Specifically, the team built a highly advanced source of entangled photon pairs and coupled it with extremely efficient photon detectors designed by NIST experts. Accordingly, the scientists were able to detect the entangled photons with remarkable efficiency.
"Our photons can no longer duck out of being measured," Zeilinger said.
Thus the loophole of certain photons going undetected in a quantum physics experiment is closed.
"Perhaps the greatest weakness of photons as a platform for quantum experiments is their vulnerability to loss," Giustina said, "but we have just demonstrated that this weakness need not be prohibitive."
While significant, the study is still just one step in fully closing the photon loopholes, given the absence of a single experiment whereby photons no longer have the possibility of behaving in a counterintuitive manner. It is clear, however, that photons are losing their ability to hide, and the study brings us one step closer to confirming the very strange nature of our universe.
