Physicists at the University of Vienna have extended the lifespan of magnons, tiny waves in magnetic materials, to 18 microseconds, a hundredfold increase over the previous limit of a few hundred nanoseconds. This breakthrough addresses a key obstacle in the development of practical quantum computers, potentially enabling devices dramatically smaller than current prototypes. Researchers achieved this by exciting short-wavelength magnons in ultra-pure spheres of yttrium iron garnet cooled to just 30 millikelvin, demonstrating that magnon lifespan is limited not by fundamental physics, but by material quality. “In this state, magnons are no longer fleeting signals, but become long-lived, reliable carriers of quantum information,” explains the team, suggesting the possibility of building a quantum computer the size of a 1-cent coin. Yttrium Iron Garnet Enables 18-Microsecond Magnon Lifetimes This advancement isn’t simply incremental; it fundamentally alters the potential scale of quantum computing hardware, suggesting devices could one day be built no larger than a 1-cent coin. The research, recently published in Science Advances, demonstrates that extending magnon lifetimes isn’t constrained by immutable physical laws, but rather by the purity of the materials used to generate them. By exciting short-wavelength magnons, inherently less susceptible to surface defects, they observed these significantly prolonged lifetimes. “Even the least pure sample surpassed all previous records,” indicating that further improvements are achievable through advancements in materials science. This discovery is crucial because it shifts the focus from theoretical physics to practical material engineering. This extended lifespan transforms magnons from fleeting signals into robust carriers of quantum information, comparable to superconducting qubits. “With lifetimes of 18 microseconds, magnons transform from lossy intermediate links into robust quantum memories and low-loss communication links on a chip,” explained the researchers. Magnons could potentially serve as a ‘quantum bus’ connecting hundreds of qubits, or as universal translators in hybrid quantum architectures,