Quantum leap in computing on hold as older devices prove faster

Quantum advantage – the moment when quantum computers can solve problems classical computers find impossible – is still some way off, a study suggests.

Current and next-generation quantum computers are unlikely to provide any advantage over traditional computing for accomplishing certain tasks unless their calculation errors – known as noise rates – decrease significantly, researchers have found.

Quantum technologies offer huge potential to deliver fast, powerful and more efficient calculations than traditional computers, experts say.

Recent progress in the design and engineering of quantum computers led a team of scientists from the Universities of Edinburgh and Copenhagen to investigate if they could outperform conventional machines for specific applications.

They examined whether quantum computing’s noise rates would prevent the new systems from outperforming classical computers on specific tasks.

Experts developed a technique to compare how classical algorithms and quantum algorithms performed on a quantum computer, in finding the best solution from a large number of options.

They found that classical methods still performed best in these so-called optimisation problems because of the large number of unavoidable imperfections in the quantum algorithms. Quantum computing is still too noisy, experts concluded.

Quantum computing combines computer science with quantum physics. These supercomputers store their data using sub-atomic particles known as qubits, instead of silicone chips used in traditional machines. Silicon chips store data in binary code – a series of ones and zeros – while qubits represent a range of values simultaneously, which allows the potential for faster calculations.

Dr Raul Garcia-Patron Sanchez, Senior Lecturer in Quantum Computing, School of Informatics, said: “Quantum computing has the potential to transform the digital world as we know it. It holds the key to the technological future of many businesses, industries and research worldwide.

“However, our research highlights the importance of effective error correction schemes and improved  engineering and design to enable quantum computers to perform better than our traditional computers, when trying to solve a family of optimization problems.”

Dr Daniel Stilck França, QMATH, Department of Mathematical Sciences, University of Copenhagen, Copenhagen, Denmark, said:  “Quantum computers hold tremendous potential to solve problems that are out of reach for current technologies. But it is unclear how far the technology has to evolve before it finds useful applications. Our work provides much needed tools to understand when this transition will happen.”

The research was published in Nature Physics and funded by Simulation Hub, an EPSRC-funded project, and Villum Fonden via the QMATH Centre of Excellence in Quantum Computing.