Scientists edge toward scalable quantum simulations on a photonic chip

Scientists have made an important step toward developing computers advanced enough to simulate complex natural phenomena at the quantum level. While these types of simulations are too cumbersome or outright impossible for classical computers to handle, photonics-based quantum computing systems could provide a solution.

A team of researchers at the University of Rochester developed a new chip-scale optical quantum simulation system that could help make such a system feasible. The team, led by Qiang Lin, an electrical and computer engineer and optics expert, published the findings in Nature Photonics.

"Scalability is a key challenge in quantum simulations, and this team is making very nice progress toward complex quantum computation."

- Dominique Dagenais

This work was performed in part at the Cornell NanoScale Facility, a member of the National Nanotechnology Coordinated Infrastructure, which is supported by the U.S. National Science Foundation. NSF also supported the work with two research grants.

Lin's team ran the simulations in a synthetic space that mimics the physical world by controlling the frequency, or color, of quantum entangled photons as time elapses. This approach differs from the traditional photonics-based computing methods in which the paths of photons are controlled, and drastically reduces the physical footprint and resource requirements.

"For the first time, we have been able to produce a quantum-correlated synthetic crystal," says Lin. "Our approach significantly extends the dimensions of the synthetic space, enabling us to perform simulations of several quantum-scale phenomena such as random walks of quantum entangled photons."

The researchers say that this system can serve as a basis for more intricate simulations in the future.

"Though the systems being simulated are well understood, this proof-of-principle experiment demonstrates the power of this new approach for scaling up to more complex simulations and computation tasks, something we are very excited to investigate in the future," says Usman Javid, the lead author of the study.

Adds Dominique Dagenais, a program director in NSF's Directorate for Engineering, "Scalability is a key challenge in quantum simulations, and this team is making very nice progress toward complex quantum computation."