Scientists use quantum computers to simulate quantum materials

Scientists are taking an important step in making quantum computing more efficient.

Quantum computers promise to revolutionize science by enabling calculations once considered impossible. But for quantum computers to become a daily reality, there is still a long way to go and many difficult tests to pass.

One of the tests involves using quantum computers to simulate material properties for next-generation quantum technologies.

In a new study from the U.S. Department of Energy’s (DOE) Argonne National Laboratory and the University of Chicago, researchers performed quantum simulations of spin defects, which are specific impurities in materials that could offer a promising basis for new quantum technologies. The study improved the accuracy of calculations on quantum computers by correcting for noise introduced by quantum hardware.

“We want to learn how to use new computing technologies that are on the rise. Developing robust strategies in the early days of quantum computing is an important first step to being able to understand how to use these machines effectively in the future.” — Giulia Galli, Argonne and University of Chicago

The research was conducted as part of the Midwest Integrated Center for Computational Materials (MICCoM), a DOE computational materials science program headquartered in Argonne, as well as Q-NEXT, a national center for computational science research. quantum information from the DOE.

“The reasons we perform these kinds of simulations are to gain a fundamental understanding of material properties and also to tell experimenters how to possibly design materials better for new technologies,” said Pritzker School professor Giulia Galli. of Molecular Engineering and the Department. in Chemistry at the University of Chicago, Principal Investigator at Argonne National Laboratory, Q-NEXT Collaborator and Director of MICCoM. “Experimental results obtained for quantum systems are often quite complex and can be difficult to interpret. Having a simulation is important to help interpret experimental results and then come up with new predictions.”

While quantum simulations have long been performed on traditional computers, quantum computers may be able to solve problems that even the most powerful traditional computers cannot solve today. Reaching that goal remains to be seen, as researchers around the work continue efforts to build and use quantum computers.

“We want to learn how to use the new computer technologies that are on the rise,” said Galli, the paper’s lead author. “Developing robust strategies in the early days of quantum computing is an important first step to being able to understand how to use these machines effectively in the future.”

Examining spin defects offers a real-world system to validate the capabilities of quantum computers.

“The vast majority of computations with quantum computers these days are on model systems,” Galli said. “These models are interesting in theory, but simulating real material of experimental interest is more valuable for the whole scientific community.”

Performing calculations of the properties of materials and molecules on quantum computers runs into a problem not encountered with a classical computer, a phenomenon known as material noise. Noisy calculations return slightly different responses each time a calculation is performed; a noisy addition operation may return values ​​slightly different from 4 each time for the question “What is 2 plus 2?”.

“The uncertainty of the measurement depends on the quantum hardware,” said Argonne scientist Marco Govoni, co-lead author of the study. “One of the accomplishments of our work is that we were able to correct our simulations to compensate for the noise we were encountering on the hardware.”

Understanding how to handle noise in quantum computers for realistic simulations is an important finding, said University of Chicago graduate student Benchen Huang, first author of the study.

“We can anticipate that in the future we may have silent quantum computing – learning how to eliminate or cancel noise in our simulation will also teach us whether quantum advantage can become a reality and for what issues in materials science. .”

Ultimately, according to Galli, the revolutionary potential of quantum computers will motivate more work in this direction.

“We’ve only just started,” she said. “The road ahead of us promises to be full of exciting challenges.”

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Material provided by DOE/Argonne National Laboratory. Original written by Jared Sagoff. Note: Content may be edited for style and length.