title: QUANTUM INFORMATION. Coherent coupling between a ferromagnetic magnon and a superconducting qubit.
abstract: Rigidity of an ordered phase in condensed matter results in collective excitation modes spatially extending to macroscopic dimensions. A magnon is a quantum of such collective excitation modes in ordered spin systems. Here, we demonstrate the coherent coupling between a single-magnon excitation in a millimeter-sized ferromagnetic sphere and a superconducting qubit, with the interaction mediated by the virtual photon excitation in a microwave cavity. We obtain the coupling strength far exceeding the damping rates, thus bringing the hybrid system into the strong coupling regime. Furthermore, we use a parametric drive to realize a tunable magnon-qubit coupling scheme. Our approach provides a versatile tool for quantum control and measurement of the magnon excitations and may lead to advances in quantum information processing.
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan. tabuchi@qc.rcast.u-tokyo.ac.jp.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tabuchi
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Ishino
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Noguchi
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan.
authors.forename: Toyofumi
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan.
authors.forename: Rekishu
authors.initials: R
authors.lastname: Yamazaki
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Usami
authors.affiliation: Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan. Center for Emergent Matter Science (CEMS), RIKEN, Wako, Saitama 351-0198, Japan.
authors.forename: Yasunobu
authors.initials: Y
authors.lastname: Nakamura