Recently, hybrid dynamic systems based on magnetic materials have attracted increasing interests as a new branch in quantum information science. Magnetic excitations, or magnons, are collective excitation of magnetic moments with frequency in the range of GHz to THz. Due to diverse coupling mechanisms, magnons can be coupled to a wide variety of excitations such as microwave, optic light, phonons and spins. They are promising for coherent information transfer between distinct physical platforms, making them promising for exploring potentials in quantum sensing and quantum transduction. 

In this talk, we will discuss two superconducting hybrid magnonics circuit platforms for implementing on-chip hybrid magnonic system. In the first platform, we embed single-crystal yttrium iron garnet (YIG) spheres in superconducting coplanar resonators. We demonstrate strong magnon-photon coupling at cryogenic temperature, and microwave-mediated distant magnon-magnon interactions by coupling two remote YIG spheres to a superconducting resonator as a coherent data bus [2]. Furthermore, we demonstrate time-domain magnon interference between the two remotely coupled YIG spheres by incorporating two perpendicular microwave antennas for direct magnon excitations and readout [3]. In the second platform, we build superconducting coplanar resonators directly on top of YIG films grown on Y₃Sc₂Ga₃O₁₂ (YSGG) substrates, and demonstrate strong coupling between propagating spin waves and microwave photons in the resonator at cryogenic temperatures. Our results introduce the first all-on-chip superconducting hybrid magnonic circuit base on low-damping YIG spheres and thin films, which will become the next-generation circuit platform for exploring propagating-magnon-based quantum information science.

[1] Y. Li et al., Strong coupling between magnons and microwave photons in on-chip ferromagnet-superconductor thin-film devices, Phys. Rev. Lett. 123, 107701 (2019)

[2] Y. Li et al., Coherent coupling of two remote magnonic resonators mediated by superconducting circuits, Phys. Rev. Lett. 128, 047701 (2022)

[3] M. Song et al., Single-shot magnon interference in a magnon-superconducting-resonator hybrid circuit, Nature Commun. 16, 3649 (2025)

Biography:

Dr. Yi Li is currently an assistant scientist at Materials Science Division at Argonne National Laboratory. He has obtained his B.S. degree in Physics from Peking University (2009) and his Ph.D. degree in Materials Science & Engineering from Columbia University (2015). Prior to Argonne he has been a postdoc at CEA Saclay in France for two years (2015-2017). Yi Li's research focuses on building hybrid quantum magnonic circuits based on microwave superconducting circuits and magnetic devices for their applications in quantum information processing. Yi was the recipient of the AVS Praire Chapter Early Career Research Award in 2024 and Argonne PSE Early Named Investigator Award in 2025. Yi also serves as the chair of the IEEE Magnetic Society, Chicago Chapter since 2024.

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