2014/05/31 by Yutaka Tabuchi, Seiichiro Ishino, T. Ishikawa +4 · 4 citations
Engineering · Physics and Astronomy · #Magneto-Optical Properties and Applications #Mechanical and Optical Resonators #Quantum optics and atomic interactions #cond-mat.mes-hall #quant-ph
paper · pdf · doi:10.1103/physrevlett.113.083603
published as Phys. Rev. Lett. 113, 083603 (2014) · 5 pages, 4 figures
openalex publication_date 2014/08/22 · arxiv created 2014/10/14 · arxiv updated 2014/10/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/31
We demonstrate large normal-mode splitting between a magnetostatic mode (the Kittel mode) in a ferromagnetic sphere of yttrium iron garnet and a microwave cavity mode. Strong coupling is achieved in the quantum regime where the average number of thermally or externally excited magnons and photons is less than one. We also confirm that the coupling strength is proportional to the square root of the number of spins. A nonmonotonic temperature dependence of the Kittel-mode linewidth is observed below 1 K and is attributed to the dissipation due to the coupling with a bath of two-level systems.