Ultralong-living magnons in the quantum limit
- Rostyslav O. Serha
- Kaitlin H. McAllister
- Fabian Majcen
- Sebastian Knauer
- Timmy Reimann
- Carsten Dubs
- Gennadii A. Melkov
- Alexander A. Serga
- Vasyl S. Tyberkevych
- Andrii V. Chumak
- Dmytro A. Bozhko
2026-05-01
Solid-state platforms based on bosonic quasiparticles offer a compelling route toward on-chip quantum information technologies scalable to nanometer dimensions. Coherence time, a key figure of merit for any quantum system, is fundamentally limited by the lifetime of quasiparticles that store quantum information. For magnons—bosonic excitations of collective magnetization dynamics—it has long been reported that their lifetime does not exceed a few hundred nanoseconds, placing a stringent constraint on their use in quantum architectures. Here, we demonstrate magnon lifetimes exceeding 18 microseconds. Experiments performed on single-crystal yttrium iron garnet spheres cooled to 30 millikelvin reveal relaxation times of short-wavelength magnons nearly two orders of magnitude longer than previously observed. These findings overturn the established view of magnon dissipation limits, positioning magnons as viable, long-lived information carriers for solid-state quantum computing.