Physicists at Wits University have shown that quantum information carried on light can survive a trip through turbulent air completely intact, even when the light itself arrives mangled beyond recognition.
The finding was published in Physical Review Letters on Tuesday. Lead author Tatjana Kleine of the Wits School of Physics worked with colleagues at Nanyang Technological University in Singapore and the University of Naples Federico II in Italy.
Interesting insights on Wits quantum breakthrough
The paper, Topological Robustness of Orbital Angular Momentum Entanglement in Stochastic Channels, reports that the topological number held exact even as the quantum state purity fell to 33%.
The commercial detail is that the effect needs no new hardware. Any lab already generating orbital angular momentum entangled photon pairs, a routine procedure, gets the topology thrown in free, so accessing it is a change in measurement strategy rather than a change in kit.
That matters for high-dimensional key distribution, long favoured over polarisation-based systems for capacity but stuck in the lab for two decades because the twist patterns fall apart in open air.
What others are saying about Wits quantum breakthrough
TechCentral reported the result and cautioned that reading a topological number is not yet the same as sending a message with it. Phys.org adds that the states scale up to higher dimensions for greater security, while TechTimes notes the protection is already built into any system distributing these photons.
The lab is winning, the country is not ready
SA is world-class at this. Andrew Forbes wrote the national quantum road map, his Structured Light Laboratory keeps landing in top journals, and its spin-out Button Optics proved the pipeline can reach a paying customer. The physics has never been the bottleneck. What is missing is the money and the urgency to commercialise it here, because the moment a working protocol exists, the buyers are banks and critical infrastructure operators watching their current encryption run out of road.
A turbulence rig is not a link across Joburg yet. But the decision about who owns the eventual product gets made now, not once Singapore has demonstrated one.
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