Physicists at the University of Vienna have announced a major breakthrough in magnon research, a development that could accelerate the creation of ultra-compact quantum computers. The study reveals that magnons, tiny waves in magnetisation, can now persist far longer than previously thought, overcoming a critical barrier in quantum technology. Magnons, which behave like ripples moving through magnetic materials, have long been considered promising components for hybrid quantum systems and precision measurement tools. However, their practical use has been limited by their extremely short lifespan, previously capped at only a few hundred nanoseconds.
In the new research, an international team led by Andrii Chumak has extended the lifetime of magnons to as much as 18 microseconds. This represents an improvement of nearly 100 times over earlier results, significantly enhancing their viability as carriers of quantum information.
The findings suggest that magnons can now act as stable and reliable quantum signals rather than fleeting phenomena. With this advancement, they may become comparable to superconducting qubits currently used in leading quantum computing systems.
A key aspect of the breakthrough lies in the researchers’ approach. Instead of relying on conventional uniform magnons, the team focused on short-wavelength magnons, which are less affected by imperfections on the surface of materials, one of the main causes of signal loss in earlier experiments.
In addition, the scientists cooled ultra-pure spheres of yttrium iron garnet to temperatures as low as 30 millikelvin using a specialised cryostat. At such extreme conditions, thermal disturbances that typically degrade magnons are effectively eliminated.
Crucially, the study challenges a long-standing assumption about magnon behaviour. The researchers discovered that the lifespan of magnons is not governed by a fundamental law of physics but is instead determined by the purity of the material used. Tests on three samples confirmed that higher purity directly correlates with longer lifetimes.
Even the least pure material tested outperformed previous benchmarks, indicating that further improvements are achievable through advances in materials science rather than new theoretical breakthroughs.
With extended lifetimes, magnons could function as quantum memory units or low-loss communication links on microchips. This opens the possibility of creating a “quantum bus” capable of connecting large numbers of qubits, a key requirement for building scalable quantum computers.
Summing up the implications, the researchers say the breakthrough could enable quantum computing devices small enough to fit on a chip the size of a coin. As materials continue to improve, magnons may also serve as universal connectors in hybrid quantum systems, linking different quantum technologies into a unified platform.
