2014

Hybridizing ferromagnetic magnons and microwave photons in the quantum limit

Tabuchi, Yutaka, Ishino, Seiichiro, Ishikawa, Toyofumi et al.

Understand

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.

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