In a series of recent publications, Los Alamos scientists have explored new ways to use quantum computers as dynamical, highly controllable experimental platforms to accelerate scientific discovery. Through a Laboratory Directed Research and Development program, an interdisciplinary team of theoretical physicists, experimental physicists, computer scientists, mathematicians and others focused on using quantum annealing platforms for practical, impactful scientific applications.
“Rather than pursuing universal quantum computing, we have shown that we can already use existing analog quantum computers and their coupled qubits to get science results today,” said Los Alamos scientist Cristiano Nisoli, who led the project. “We employed analog quantum computers as building blocks to realize quantum systems analogous to physical materials, and then perform incredibly controlled experiments on them, demonstrating significant capabilities that go beyond computation.”
Mimicking lab experiments: Hysteresis
The team has worked to perform, for the first time, hysteresis experiments on quantum computers. Hysteresis is a characteristic of magnetic systems where the magnetization response of the system to an applied field depends on the history of previously applied fields; that is, hysteresis is a memory effect, where a current state is influenced by a prior state. Especially in frustrated magnetic systems, where interactions among magnetic moments cannot be all satisfied at the same time, changing a few experimental parameters reveals complex behaviors.
Hysteresis proves difficult to simulate with standard computers, where it requires many ad-hoc choices about the kinetics involved with shifting data and variables. Importantly, in quantum platforms, coupled qubits naturally evolve under quantum fluctuations with no a-priori assumptions.
Los Alamos scientist Elijah Pelofske proposed employing a hardware control parameter in D-Wave machines to apply a time-varying field while the system is exposed to quantum fluctuations. Though analog quantum computers like the D-Wave machines were initially developed as combinatorial optimization tools, the team’s approach found them suited to memory-related problems such as hysteresis. As described in Science Advances, the team’s work opens up a line of research that sees analog quantum computer platforms used for probing magnetic phenomena, bringing analog quantum computers into fundamental questions in condensed matter physics.
Magnetic memory and hysteresis from quantum transitions
Los Alamos scientists have looked into theoretical explanations for the underlying physics in how analog quantum computers handle memory in relationship to quantum physics problems. While quantum annealing memory effects are reduced by quantum tunneling, hysteresis can still occur. Los Alamos scientist Frank Barrows led the building of a conceptual framework to understand the behavior of qubits in these scenarios at a deeper level in ways that might be applicable to quantum molecules.
These results establish programmable analog quantum computers as powerful testbeds for exploring memory-endowed non-equilibrium dynamics in quantum many-body systems.
“By reproducing and dissecting complex hysteresis phenomena observed in specific compounds under high-magnetic fields, the quantum platform becomes a powerful interpretive tool,” Nisoli said. “It’s like having a companion experiment where you can turn every knob independently and see what matters. That’s not as easily accessible in standard experiments.”
Shannon information entropy investigations
Further research at the Laboratory led by Pelofske has employed Shannon information entropy to quantify classical configuration memory retention under quantum fluctuations. Shannon information entropy quantifies the randomness of the outcome of a variable. The new method has been applied to shed light on memory retention or loss in a quantum system when subjected to quantum fluctuations.
The team couples the study of alternative classical approaches with an exploration of the classical spin noise of the problems. The combination of approaches seeks to illuminate the nature of the experiments and differentiate between their quantum or classical nature. The team’s approach helps establish a general probe of the interplay between quantum fluctuations and memory.
Zooming in on criticality and temperature
In another first, the Los Alamos team pushed a D-Wave quantum annealing machine to the limits of Boltzmann sampling, demonstrating for the first time that the analog quantum computer can be faithful enough to implement fine methods from statistical mechanics, such as the renormalization group, to study a system at criticality — at the points in which the system transforms from one phase to another and maintains itself in scale-free and essentially fractal state.
As described in Nature Communications, the team found that their quantum annealing approach can be used to study criticality in classical statistical physics models.
“These results establish analog quantum computers as robust simulators for statistical physics, offering a new pathway to study phase transitions and critical behavior,” said Pratik Sathe, former Lab postdoctoral researcher and current staff member at D-Wave Quantum, who led the work. “Remarkably, we find that annealing-based sampling does not suffer from critical slowing down and, therefore, avoids the ad-hoc techniques typically required to study criticality in frustrated systems using classical computational methods.”
This use of analog quantum computers as simulators of thermodynamics has also spurred the investigation of thermometry of these machines. The Los Alamos scientists sought to check how faithfully systems embedded in an analog quantum computer can reproduce the statistics of a thermal one.
“We asked ourselves, can the temperature of a system embedded in an analog quantum computer be controlled, and how?” said Los Alamos scientist George Grattan, first author of a work that, for the first time, seeks to check how faithfully these systems can reproduce the statistics of a thermal ensemble.
Driving useful experiments with quantum annealing
The Los Alamos team’s approach reflects a commitment to using today’s analog quantum computers as experimental platforms for physics, not just as computational devices. The team’s results sharply contrast with the idea that near-term noisy quantum hardware can only deliver narrow or artificial demonstrations on small or uninteresting systems.
With meaningful impact across multiple, independent topic areas — non-equilibrium dynamics, hysteresis and memory, critical phenomena, Boltzmann sampling, and now materials-relevant behavior — the team is able to move their approaches beyond abstract models, including working with experimentalists at the National High Magnetic Field Laboratory’s Pulsed Field Facility (MagLab) at the Laboratory.
“This work opens the door to a new research and development workflow bringing together quantum theory, computation and experiment,” said Carleton Coffrin, principal investigator of the quantum annealing project and the Laboratory’s Quantum Science Coordinator. “The broad perception in the quantum computing research community is that this technology is immensely promising but not useful today, and that we need much larger, fault-tolerant machines before quantum computing can have real scientific impact. However, this team is demonstrating that for some carefully selected applications, analog quantum hardware is immediately useful for scientific discovery, and a novel tool for theoretical and experimental research.”
Paper: “Classical Criticality via Quantum Annealing.” Nature Communications. DOI: 10.1038/s41467-025-67568-w
Funding: This work was supported by Laboratory Directed Research and Development program at Los Alamos.
Paper: “Magnetic Hysteresis Experiments Performed on Quantum Annealers.” Science Advances. DOI: 10.1126/sciadv.aeb5192
Funding: This work was supported by the Laboratory Directed Research and Development program at Los Alamos, the Advanced Simulation and Computing Program, and the New Mexico Consortium.
Paper: “Erasing Classical Memory with Quantum Fluctuations: Shannon Information Entropy of Reverse Quantum Annealing.” ArXiv. DOI: 10.48550/arXiv.2509.10927
Funding: The research supported by the Laboratory Directed Research and Development program at Los Alamos.
Paper: “Magnetic Memory and Hysteresis from Quantum Transitions: Theory and Experiments on Quantum Annealers.” ArXiv. DOI: 10.48550/arXiv.2507.18079
Funding: The research was supported by the Laboratory Directed Research and Development program at Los Alamos.
Paper: “Classical Thermometry of Quantum Annealers” ArXiv. DOI: 10.48550/arXiv.2512.03162
Funding: The research was supported by the Laboratory Directed Research and Development program at Los Alamos.
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