RQC Seminar

234th RQC Seminar

• Speaker

  Prof. Li FuLi
  ( School of Physics, Xi'an Jiaotong University, China )

• Date

  16:00 - 17:00 (4:00 p.m. - 5:00 p.m.), November 11, 2025 Tuesday)

• Venue

  Hybrid(ZOOM・ Wako Main Research Bldg. 3F 345-347 Seminar Room / 研究本館3階 345-347 セミナー室 (C01))

• Title

  Chiral Coupling and Nonreciprocal Single-Photon Quantum Router

• Inquiries

  norilab_rqc_assist[at]ml.riken.jp

Abstract
Chiral coupling at the single-quantum level promises to be a remarkable potential for quantum information processing. In this talk, I shall introduce a scheme for the realization of a chiral interaction between a magnon mode in a ferromagnetic sphere and a superconducting qubit mediated by a one-dimensional coupled-cavity array. When the qubit is coupled to two lattice sites of the array and each one is encoded with a tunable phase, a directional qubit-magnon interaction can be generated via the quantum interference effect. The chiral coupling may be used to control the single-quantum-level photon transmission. Then, I shall talk about an efficient scheme for the implementation of a nonreciprocal single-photon quantum router. I shall show that the nonreciprocity can berealized by unidirectionally interacting the rotating microwave modes of the ring resonator with a dissipative magnon mode in an yttrium iron garnet disk. We find that a single-photon signal can be delivered from a given input port to either of the two output ports, but is fully absorbed from the opposite one. These works opens up an alternative route to construct chiral devices and nonreciprocal single-photon quantum router for quantum networks.