[14p-B8-1~10] Hybrid Quantum Information Science and Technology

[14p-B8-6] Hybrid Quantum System Consisting of Ferromagnetic Spin Excitations and a Superconducting Qubit

〇Yasunobu Nakamura^1,2 (1.RCAST UTokyo, 2.CEMS RIKEN)

Keywords:quantum bit, superconductivity, magnon

Superconducting qubits have a large dipole moment and interact strongly with electromagnetic fields. Because of the property, they are widely applied to hybrid quantum systems, where different types of quantum systems are combined so that we can utilize their advantages for constructing useful quantum devices. Here we focus on collective spin excitations in a millimeter-scale single-crystalline sphere of ferromagnetic insulator. We put a sphere of single-crystalline yttrium iron garnet (YIG) and a superconducting qubit in a copper-made microwave cavity. They interact each other via virtual excitations of photons in microwave modes in the cavity. We observe coherent interaction of magnons, quanta of collective spin excitations and demonstrate coherent control of the quantum state of magnon excitations. We are also woking on coherent interaction between magnons and optical photons with communication wavelength.