The most extreme “entanglement” between pairs of photons ever seen in the lab has been reported by researchers from the Centre for Quantum Technologies (CQT) at the National University of Singapore and the University of Seville in Spain.
Quantum entanglement says that particles on opposite sides of the universe can be intrinsically linked so that they share information instantly. It was an idea that Einstein scoffed at.
This discovery provides evidence for the validity of quantum physics and will bolster confidence in quantum cryptography and quantum computing based on this phenomenon.
“For some quantum technologies to work as we intend, we need to be confident that quantum physics is complete,” said Poh Hou Shun, who carried out the experiment at CQT. “Our new result increases that confidence,” he said.
“You need a very precise measurement to be able to distinguish the quantum limit, and that was our achievement,” said Christian Kurtsiefer, a Principal Investigator at CQT and co-author on the paper.
Entanglement can be used for secret messaging and to speed up some calculations. Checking that it’s possible to reach the quantum limit for correlations is valuable for these applications as their security and reliability depends on this limit being fundamental.