Description:

Abstract:

Hybrid dynamic systems have recently attracted great attention due to their applications in quantum computing, communications, and sensing. In particular, they provide a new paradigm for combining platforms and devices that can perform different tasks such as storing, processing, and transmitting coherent states. In this talk, I will discuss the potential in quantum information processing brought by magnon—the collective excitations of magnetization. Magnons exhibit a few key features making them highly competitive in quantum information processing, namely their strong coupling to microwave photons, their extraordinary tunability and flexibility for chip-based circuit integration. In particular, we focus on the integration of magnetic materials and devices with superconducting microwave circuits which is compatible with other major quantum modules. In the first part, I will demonstrate strong coupling between magnons and microwave photons by integrating Ni80Fe20 (permalloy) thin-film devices with coplanar superconducting resonators, allowing for high coupling efficiency and device miniaturization. In the second part, I will utilize single-crystal Y3Fe5O12 (YIG) spheres and show how they can also be chip-embedded with superconducting resonators. We achieve state-of-the-art magnon decoherence rate down to 1 MHz and sub-gigahertz magnon-photon coupling strength. With the new platform, we also achieve coherent level repulsion and dissipative level attraction between the magnon modes of the two remote YIG spheres. Our results open new avenues towards integrating hybrid magnonic networks for coherent information processing on a quantum-compatible superconducting platform.

Speaker: Dr. Yi Li, Argonne National Laboratory

Host: John Ketterson

Speaker Bio: 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 Postdoctoral Performance Awards (2020) at Argonne National Laboratory and the IEEE Chicago "Distinguished R&D" Award (2020) for his pioneering work on magnon-photon coupling in superconducting resonator for Quantum Information Science.