Researchers at the University of Vienna have extended the lifetime of magnons from a few hundred nanoseconds to 18 microseconds — nearly a hundredfold gain that puts these magnetic waves on par with the superconducting qubits inside today's leading quantum processors. The finding appears in Science Advances, in a study led by Andrii Chumak and built on doctoral experiments by Rostyslav Serha.

The number matters because magnons have spent their career as a laboratory curiosity with a timekeeping problem. Until now, they vanished too quickly to store or move quantum information. Eighteen microseconds changes that verdict.

What are magnons?

Magnons are waves of magnetization that travel through magnetic solids — ripples on a pond, if the pond were a crystal and the stone were a spin flip. Unlike photons, they do not need optical fiber or empty space. They stay inside the material.

Their wavelengths can shrink to a few nanometers, which is why the Vienna group talks about quantum circuits on chips the size of a one-cent coin — the same real estate as a smartphone processor. Magnons also interact naturally with phonons and photons, a useful trait for hybrid quantum systems and quantum metrology.

How did the team do it?

Two techniques, combined. First, the researchers abandoned uniform magnons in favor of short-wavelength magnons, which are less sensitive to surface defects that cut lifetimes short in earlier experiments. Second, they cooled ultra-pure yttrium iron garnet (YIG) spheres to 30 millikelvin in a mixed-phase cryostat, freezing out the thermal processes that normally destroy the waves.

Then came the more consequential discovery. The team tested three YIG spheres of differing purity and found a clean pattern: the purer the crystal, the longer the magnons survived. Even the least pure sample outperformed every prior experiment.

The limit, in other words, is not a law of physics. It is a matter of crystal quality — which places the next gains in the hands of materials engineers rather than theorists waiting for a new discovery.

Why does this matter for quantum computing?

At 18 microseconds, a magnon is no longer a transient signal. It is a candidate component.

• Quantum memory: long-enough-lived states to hold information on a chip.
• Low-loss interconnects: channels that carry quantum information between qubits.
• A quantum bus: a shared pathway that could link hundreds of qubits in one machine.

The researchers also point to magnons as universal translators. Because they couple naturally with many quantum systems, they could let technologies that normally cannot talk to each other share a chip. That is the kind of plumbing problem scaling a quantum computer actually requires.

What happens next?

The path forward runs through manufacturing, not physics. Purer YIG crystals should push lifetimes further, and the Vienna collaboration — which included the University of Colorado, Colorado Springs, plus institutions in Germany, the United States and Ukraine — frames the current 18 microseconds as a floor set by today's materials rather than a ceiling. If crystal purity keeps improving, coin-sized quantum hardware graduates from speculation to roadmap.

By Nathan Brooks, Chip Dispatch