Software breakthrough could spur quantum computer advances

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.

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 team says. 

Light-based quantum devices

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, the team says. 

Key to informing the creation of bigger, more reliable quantum computers is the development of algorithms to simulate how devices might work in reality, the team says. 

However, running these simulations has until now required vast amounts of computing power available at only a handful of facilities worldwide, the team says. 

Now, a team led by researchers at the University of Edinburgh and EPCC has developed an algorithm that enables the simulations to be run using around five per cent of the computing power previously needed to perform them with a supercomputer. This means the simulations can be run by a powerful desktop computer, the team says.

Their 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.

Gaussian boson sampling

Their algorithm for the first time enables standard computers to run so-called Gaussian boson sampling, a simulation designed to demonstrate the superior capabilities of quantum devices powered by light – so-called photonic quantum computers. 

In their tests, the team 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 enable researchers to simulate light-based quantum computing in unprecedented detail, the team says. 

The research, published in the journal Science Advances, also involved scientists from the University of Montreal, 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-size 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.”

Links

Read the paper in Science Advances: A fast and frugal Gaussian boson sampling emulator

Research at EPCC

Quantum computing at EPCC

EPCC’s Quantum Applications Group is exploring how quantum computing will impact HPC and Data Science. We are actively searching for applications of quantum computing, and investigating the required quantum and classical resources to achieve an advantage in computability, performance, or energy. We are also developing hybrid quantum and classical programming models, focusing on those which suitable for HPC. Finally, we are developing and improving our ability to simulate quantum computing using our classical HPC resources to better support quantum algorithm and application development.

We are collaborating directly with quantum computing experts across the UK through these organisations:

• Quantum Computing Application Cluster
  A multi-disciplinary collaboration between the Universities of Edinburgh, Glasgow, and Strathclyde that is working to accelerate the development of quantum computing technologies in Scotland.
• Quantum Software Lab
  A dedicated Quantum Software Lab at the University of Edinburgh that works alongside the National Quantum Computing Centre to identify, develop, and validate real-world use cases for quantum computing.