Anyone walking into a university physics lab today would be forgiven for thinking they’d stumbled into an Arthur C Clarke novel in which magic was genuinely turning into technology – after all, that’s what seems to be happening with quantum computers.
Clarke observed that any adequately advanced technology was impossible to differentiate from magic. For decades, quantum computing was magic – belonging in science fiction rather than data centres.
Today, however, we have academic researchers wearing white lab coats peering into circuitry that is the bleeding edge of quantum computing.
While major companies and governments are developing increasingly advanced experimental quantum processors – IBM's Condor, announced in 2023, was the first to surpass 1 000 qubits at 1 121 – qubit count alone doesn't indicate practical computing power.
When coherence time, gate fidelity, error correction and the ability to run useful algorithms at scale are mastered, monetisation becomes possible, and today's processors will look like toy notebooks by comparison.
From South Africa to Canada and the United Kingdom, physicists, mathematicians, engineers and computer scientists are quietly rewriting the rules of computing.
The task team
Locally, researchers are contributing through the South African Quantum Technology Initiative, bringing together the University of the Witwatersrand, Stellenbosch and the University of KwaZulu-Natal.
In some cases, forget Star Trek because Wits researchers have demonstrated teleportation of high-dimensional patterns of light – transferring quantum information, not physical objects or matter – between locations. This is a key breakthrough as it's one of the stepping stones towards future quantum networks and the quantum internet.
Wits has showcased quantum secret sharing, where information is split between multiple parties so that no single participant has the whole secret.
In Canada, the Toronto-based University of Waterloo is home to the Institute for Quantum Computing, which has a multidisciplinary approach to the field of quantum information processing. Led by physics professor Norbert Lütkenhaus, it hosts researchers across seven departments and three faculties.
(If you are ever in Toronto, they have open houses and tours for the public.)
One of the institute's recent breakthroughs involved qudits. Unlike qubits, which can hold two quantum values, qudits can hold several. Apart from being a confusing two-letter difference for dyslexics, they enabled researchers to build quantum circuits up to 10 times smaller, making it possible to tackle particle physics problems that had previously been beyond the reach of conventional methods.
Qudits, rowing and cosmic rays
Cambridge and Oxford Universities, in the spirit of their famous Boat Race rivalry, used to share The Centre for Quantum Computation (CQC), founded by professor Artur Ekert in 1998.
Among CQC’s most celebrated breakthroughs is Andrew Steane's 1995 development of the Steane code, which tackled one of quantum computing's greatest challenges: keeping quantum information stable.
The Steane code showed that qubits could be shielded against certain types of disturbance – from heat and electromagnetic interference, to even cosmic rays – helping establish the principles for protecting quantum information and paving the way for practical, scalable quantum computers.
Having split from Oxford in 2010, the Cambridge groups now form the Cambridge Centre for Quantum Information and Foundations and they’re working on physics-level security through Relativistic Cryptography and have pioneered “quantum tagging” – location-based quantum cryptography protocols to better protect assets. Like laptops with top-secret information on them.
Game on
Wits has also showcased quantum secret sharing, where information is split between multiple parties so that no single participant has the whole secret.
First developed in 1998, Professor Andrew Forbes advanced it with an 11-dimensional, 10-party protocol in 2020 – moving quantum technology closer to networks capable of securely sharing information among many users rather than just two.
Which is just as well since the Cyber Threat Alliance last year, in the report “Approaching Quantum Dawn: Closing the cyber security readiness gap before it's too late”, warned that adversaries are planning for a world where today's encryption standards can be broken – and that the same advances offering security benefits are producing capabilities that render current cryptographic systems fragile.
It’s Peter Shor’s 1994 warning all over again, now in a more advanced computing environment. The fact that the good guys are building quantum machines doesn’t negate the reality that they might be used by a hostile government to break many of the encryption systems underpinning the modern internet.
South African organisations need to act by starting to plan for post-quantum cryptography now, reviewing encryption dependencies, building cryptographic inventories and raising awareness of quantum-related risks. Migration to quantum-safe systems will take years and the race has already quietly started.
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