Magnetic materials can be described in terms of magnetic particles called spins. Each spin has a preferred orientation based on the behavior of its neighboring spins, but rare earth tetraborides are frustrated, meaning these orientations are incompatible with each other. As a result, the spins are forced to compromise on a collective configuration, leading to exotic behavior such as fractional magnetization plateaus. This peculiar behavior occurs when an applied magnetic field, which normally causes all spins to point in one direction, affects only some spins in the usual way while others point in the opposite direction instead.
Using a Monte Carlo simulation technique powered by the quantum evolution of the Ising model, the team evaluated this phenomenon in microscopic detail.
“We came up with new ways to represent the boundaries, or edges, of the material to trick the quantum computer into thinking that the material was effectively infinite, and that turned out to be crucial for correctly answering materials science questions,” said co-corresponding author Travis Humble. Humble is an ORNL researcher and deputy director of the Quantum Science Center, or QSC, a DOE Quantum Information Science Research Center established at ORNL in 2020. The individuals and institutions involved in this research are QSC members.
Quantum resources have previously simulated small molecules to examine chemical or material systems. Yet, studying magnetic materials that contain thousands of atoms is possible because of the size and versatility of D-Wave’s quantum device.
“D-Wave processors are now being used to simulate magnetic systems of practical interest, resembling real compounds. This is a big deal and takes us from the notepad to the lab,” said Andrew King, director of performance research at D-Wave. “The ultimate goal is to study phenomena that are intractable for classical computing and outside the reach of known experimental methods.”
The researchers anticipate that their novel simulations will serve as a foundation to streamline future efforts on next-generation quantum computers. In the meantime, they plan to conduct related research through the QSC, from testing different models and materials to performing experimental measurements to validate the results.
“We completed the largest simulation possible for this model on the largest quantum computer available at the time, and the results demonstrated the significant promise of using these techniques for materials science studies going forward,” Kairys said.
This work was funded by the DOE Office of Science Early Career Research Program. Access to the D-Wave 2000Q system was provided through the Quantum Computing User Program managed by the Oak Ridge Leadership Computing Facility, a DOE Office of Science user facility located at ORNL. Research performed at ORNL’s Spallation Neutron Source, also a DOE Office of Science user facility located at ORNL, was supported by the DOE Office of Science.
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Source: Elizabeth Rosenthal, ORNL