A major software advance could aid the creation of bigger, more reliable quantum computers, a study suggests.
Researchers have developed an algorithm that enables off-the-shelf computers to run quantum simulations previously only possible using the world's most powerful supercomputers.
It means the simulations can be run using around five per cent of the computing power previously needed to perform them with a supercomputer, the team says.
The advance could make it cheaper and easier to run experiments vital for understanding the limitations of current quantum computers and informing the design of improved devices, experts say.
Quantum computers could, in theory, perform calculations far beyond the capabilities of even the most advanced supercomputers, but current devices are small and error-prone, hindering their performance.
Key to informing the creation of bigger, more reliable quantum computers is the development of algorithms to simulate how devices might work in reality. However, running these simulations has until now required vast amounts of computing power available at only a handful of facilities worldwide.
The new algorithm was developed by a team led by scientists at the University of Edinburgh and EPCC, the UK's first National Supercomputing Centre, which is part of the University.
The work could aid the development of light-based quantum devices, one of several branches of current quantum research by academics and industry, the team says.
For the first time, the algorithm enables standard computers to run so-called Gaussian boson sampling, a simulation designed to demonstrate the superior capabilities of quantum devices powered by light – known as photonic quantum computers.
In tests, researchers found that classical computers using the algorithm could match and even outperform some current quantum devices' ability to run the simulations.
Researchers are working on scaling up how the algorithm is used, potentially enabling much larger simulations to be run using the same computing power. This could allow scientists to simulate photonic quantum computers in unprecedented detail, the team says.
The research, published in the journal Science Advances, also involved scientists from Polytechnique Montréal, Canada. It received support from the UK's Engineering and Physical Sciences Research Council (EPSRC) and the Natural Sciences and Engineering Research Council of Canada.
Dr Raul Garcia-Patron Sanchez, of the University of Edinburgh's School of Informatics, who led the study, said: "Classical simulation of large-scale quantum computing circuits has been achieved so far via a combination of clever algorithms and the intensive use of supercomputing facilities. Our work has contributed significant improvements in memory use, running time and energy costs in the simulation of photonic quantum computing devices, making mainstream what was before only accessible to a handful of facilities in the world."
