According to a study published in Physical Review Letters, researchers from Chalmers University of Technology in Sweden, Aalto University, and the University of Helsinki in Finland have discovered a new form of exotic quantum material and a way to create stability via magnetism.
Illustration of a new strategy to create materials with robust quantum properties, by harnessing magnetic interactions (represented by the red and blue arrows). The small green spheres represent sites where electrons can reside and move along the chain. Special magnetic atoms (purple spheres with arrows) interact with the electrons at certain sites, shown by the blueish clouds. These interactions create protected edge states (green cloud) that could help make quantum computers more stable and less sensitive to noise. Image Credit: Jose L. Lado
The sensitivity of quantum computers to environmental disturbances currently impedes their adoption. This discoveryhas the potential to significantly enhance the resilience of quantum computers, allowing them to handle quantum calculations in practice.
Physics gets weird at the atomic scale. Down there, particles follow the rules of quantum mechanics - they can exist in multiple states at once and influence each other in ways classical physics can’t explain. These strange but powerful behaviors are what make quantum computing possible, opening the door to solving problems that are out of reach for today’s most advanced supercomputers.
However, a significant problem must be resolved by physicists before quantum computations can actually be put to use. The fundamental building blocks of a quantum computer, known as qubits, are incredibly fragile. The qubits lose their quantum states and, thus, their capacity to consistently execute complicated calculations when the temperature, magnetic field, or even minuscule vibrations vary even slightly.
To address the issue, researchers in recent years have begun to investigate the possibilities of developing materials that might give greater protection against certain sorts of disturbances and noise in their fundamental structure-topology.
Topological excitations are quantum states that develop and are sustained due to the structure of the material used in qubits. They are much more stable and resilient than others. The issue remains in identifying materials that naturally enable such strong quantum states.
Newly Developed Material Protects Against Disturbances
A research team from Chalmers University of Technology, Aalto University, and the University of Helsinki has produced a novel quantum material for qubits with strong topological excitations. The accomplishment is a significant step toward achieving viable topological quantum computing by including stability into the material's architecture.
This is a completely new type of exotic quantum material that can maintain its quantum properties when exposed to external disturbances. It can contribute to the development of quantum computers robust enough to tackle quantum calculations in practice.
Guangze Chen, Study Lead Author and Postdoctoral Researcher, Applied Quantum Physics, Chalmers University of Technology
The phrase “exotic quantum materials” refers to numerous distinctive types of solids with extraordinary quantum characteristics. Finding materials with rare resilience and stability has long been a challenging pursuit in this field.
Magnetism is the Key in the New Strategy
Traditionally, researchers have used a well-established ‘recipe’ based on spin-orbit coupling, a quantum interaction that connects an electron's spin to its orbit around the atomic nucleus to generate topological excitations. However, because this ‘ingredient’ is rather scarce, the process can only be used on a restricted range of materials.
In the study, the researchers describe a whole new approach for achieving the same result using magnetism, a far more common and accessible property. The researchers were able to produce the strong topological excitations needed for topological quantum computing by using magnetic interactions.
“The advantage of our method is that magnetism exists naturally in many materials. You can compare it to baking with everyday ingredients rather than using rare spices. This means that we can now search for topological properties in a much broader spectrum of materials, including those that have previously been overlooked.” explains Guangze Chen.
Paving the Way for Next-Generation Quantum Computer Platforms
To speed the identification of novel materials with beneficial topological features, the research team created a new computational method. The tool can directly determine how strongly a material shows topological behavior.
Chen concluded, “Our hope is that this approach can help guide the discovery of many more exotic materials. Ultimately, this can lead to next-generation quantum computer platforms, built on materials that are naturally resistant to the kind of disturbances that plague current systems.”
Journal Reference:
Lippo, Z., et al. (2025) Topological Zero Modes and Correlation Pumping in an Engineered Kondo Lattice. Physical Review Letters. doi.org/10.1103/PhysRevLett.134.116605