A Scottish software breakthrough could spur big quantum computer advance

Researchers have developed an algorithm that allows off-the-shelf computers to run quantum simulations previously only possible using the world’s most powerful supercomputers.

A major software breakthrough could spur a big advance in creating quantum computers, according to a University of Edinburgh-led study.

Researchers have developed an algorithm that allows 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 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.

The University of Edinburgh’s Dr Raul Garcia-Patron Sanchez, 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.”

Read more: Switch-on of supercomputer the size of a supermarket now 'tantalisingly close'

In theory, quantum computers could perform calculations far beyond the capabilities of even the most advanced supercomputers. But current devices are small and error-prone, which hinders their performance.

The development of algorithms to simulate how devices might work in reality is key to the creation of bigger, more reliable quantum computers.

But 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. This is 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.

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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.

Last month it was reported that switch-on of a supercomputer on the outskirts of Edinburgh – which will be the size of a large supermarket once completed – is now “tantalisingly close”.

The frame of the building at a site near Roslin, Midlothian, has now been completed with the final structural beam in place.

The beam was signed by AI Minister Kanishka Narayan, Professor Kim Graham, the Provost of the University of Edinburgh and Professor Mark Parsons, director of EPCC, the national supercomputing centre led by the university.

The supercomputer, which will work on major discoveries in fields such as sustainable aircraft engineering, extreme weather events and drug discovery, is due to be operational by early 2028.