Software breakthrough could spur quantum computer advances

The study, led by researchers from the University of Edinburgh's School of Informatics and EPCC, demonstrates an algorithm capable of running quantum simulations previously thought to require some of the world's most powerful supercomputers using a fraction of the computing resources.

The work was carried out by Tom Dodd, Raul Garcia-Patron Sanchez, Oliver Brown and collaborators from Polytechnique Montréal.

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 pursued by academics and industry.

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 now working on scaling up the approach, 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 research 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.